TC Kline Smart DA - HP Autowerks Review (long)

Let me first start off by saying I’m not extremely technical but I do have some suspension experience with my E46, sport bikes and spend a good bit of time at the track supporting various friends both car and motorcycle. My E46 was fairly highly modded. In terms of suspension I had: UUC sways, Ground Control bits, RSM etc, and Bilstein PSS9s. When I purchased my M3 I was very unhappy esthetically with the wheel gap. At the time, I decided to purchase lowering springs with the intent of purchasing a coilover suspension once the market matured a bit and there were products I felt were a large performance increase over the stock suspension.

I purchased the H&R sport plus springs which interestingly are sometimes called race version and on H&Rs website it lists them as the race part number from EAS. These springs claimed a 1 inch front drop and .6 in the rear. I actually think it’s slightly more than that in the front. The race springs have a higher spring rate and are progressive. They don’t publish rate so it’s hard to know what they really are and since it’s non-linear I’m not sure how much help it would be. I can say visually it made the car much more appealing. The ride was firm but really not a problem for me. I daily drive the car about 90 miles a day and pretty much always leave the edc set for sport. Well, I’ve had the springs for about 2.5 or so years and now the car has 65k on it and I can feel the stock dampers starting to go.

I launched into a pretty exhaustive search about which coilovers to switch to based on some great information like rldzhao’s thread and then various reviews of KW, AST, Moton, Ground Control, TC Kline etc. I must say there are some outstanding threads contributed by members with excellent information. I really needed a quality suspension without a crazy rebuild cycle. I needed a suspension that wouldn’t kill me during daily use. I wanted a suspension I could use for some track days and that was a performance upgrade from stock. The biggest “challenge” is that there are many quality suspensions available for our cars and the suspension ride quality is very subjective.

I had kind of committed to a double adjustable or triple because I felt the flexibility of individual compression and rebound adjustments would allow me to dial the suspension in to better suit my needs. At this point, I contacted Harold from HP Autowerks. Harold suggested the TCK DAs paired with Swift springs. I had been strongly leaning toward ASTs but Harold felt the design of the dampers vs the monotube design of the ASTs would allow for a more compliant street driving experience. I decided on 728lb rears with 448lb fronts.

Also included in my setup are Vorshlag camber plates, HPA adjustable sway bar links and Swift springs and thrust sheets. Harold’s customer service has been outstanding dealing with about 20 different questions I had. I would highly recommend him. Tomorrow, I have new tint being installed and the car goes the GT Performance here in Maryland on Friday for install. Check back for pictures and a review to follow.

Fairly current look with H&Rs for reference:

Update: After the weekend install I can say overall I'm very happy. In all honesty, any negatives I would say are my fault rather than TCK or HPA. The good: the suspension is outstanding. I would say, in terms of ride quality, it is actually better than the stock EDC comfort setting. Granted this is all based on street driving. With the H&Rs the car would never settle while in a turn. I would constantly be fighting the car as the stock dampers probably could not handle the spring rates. I notice on their site it does say they highly suggest aftermarket dampers paired with those springs. The TCKs truly transform the handling. The car is planted and very compliant. The settings for rebound and compression are both set is the mid range so there is considerable amount of adjustment left. I will also put up my alignment settings but the camber is at the max of the BMW factory acceptable range which I believe was around 1.5 neg front and 1.7 neg rear. Like I said I drive about 90 miles each day and I don't want to much inside edge tire wear. The less than good: I probably should have gone with a higher spring rate. Ride quality is very subjective and I know for myself I could have easily tolerated a higher spring rate. The other concern for me is an aesthetic one. The front is set at its lowest and with a 7" spring there is still about 1 - 1.25 inches of gap. I'm sure if the car was corner balanced that performance wise this is appropriate however for me visually I would prefer the suspension was lower. I'm talking to Harold today to discuss my options. Again none of these "issues" are TCK or HPA issues they are purely mine and from the performance stand point I could very well be lessening the performance to gain appearance. The last issue has nothing to do with suspension but I feel important to share. I had been running 295/30 Hankooks on my Volk TE37s and switched to Michelin Pilot Super Sports. Well, the profile and a slight difference in the width is making them rub in the rear even though the rear is now actually a bit higher than it was with the springs. I plan on adding some more negative camber and this might be enough that it won't rub.
Picture of current setup

The TCK D/As get incredible reviews for the E46 M3 platform. I am looking forward to hearing how they are on the E90 M3! Keep us posted.

Harold is great to deal with. My buddy went with a tckline set up for his 135 and it has transformed the car.

Really nice looking car! I have worked with Harold on an AST suspension and I have nothing but positive things to say.

I got all my 135 suspensions bits from Harold,really helpful experienced guy.
Thanks for the write up & sick looking ride !

Car looks good as-is. Can't wait to see it after the new suspension.

OP, congrats on your new suspension....you will love it!

....in for pics

Yep, Harold is a good dude, that's who I used. I wouldn't mind trying out the TC Klines. My ASTs perform very well!

updated...

Your spring rates seem right for a dual purpose car, try stiffening the shocks a touch to get the feel you want.

IMO that ride height looks awesome

If i ever got seriously into tracking my car id rather go TCK than KW.

Glad to see TCK get some positive feedback here on M3post

After speaking with Harold this afternoon I've decided to change nothing but the suspension settings. Stalker was dead on that I needed to make adjustments. Tonight I've dailed more stiffness into the compression in the rear and into the front rebound. I'm waiting on the rest of the optimal settings from Harold. In the future, I could always swap out springs for lower front springs. Again Harold and HP Autowerks service has been exceptional. I'll take some better pictures this weekend. I'm also going to add some negative campber to the rear to try to address the rubbing. Hopefully that will be enough rather than having to switch to a 285.

I think it looks fine at this ride height.

Harold sent me the optimized settings however I have not had a chance to adjust them since last night. I can say that even with the adjustments I made last night there is an incredible range of adjustment. I would say that just changing 2 clicks of compression on the rear was equal to about the entire range of adjustment on my Bilstein PSS9s on my E46. Pretty amazing.

KennyPowers wrote

IMO that ride height looks awesome

If i ever got seriously into tracking my car id rather go TCK than KW.

Glad to see TCK get some positive feedback here on M3post

Agreed!!

Any lower and it'll look rice. Enjoy the suspension.

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I couldn't picture your car when we spoke on the phone. Your car looks great! If anything, I would get the rear slightly lower for less of a rake, but that could be just the photo doing its trick. You will need to measure it to be sure.

Lower is not better in this case. These cars need all the compression travel they can get to handle all the road imperfections and bumps. Otherwise the car just gets upset from each little bump you hit, not to mention the negative affect on the handling.

Here's another quick update: I took the car back to GTP to increase the negative camber in the rear to account for the rubbing I'm having with the 295 Pilot SS on my Volks. I'm now running 2.5 degrees neg. I also adjusted the suspension and am now very happy with the setup for my tastes. I'm running 6 out of 9 clicks in the rear for compression. (9 being full stiff) and 8 out of 12 clicks in the front for compression. For rebound I'm running front 2 sweeps from full soft, rear rebound at at 1.5 sweep from full soft.

Blade or Harold feel free to comment here.

To a suspension layman like myself, what are the major advantages/disadvantages of the TCK vs. AST. I will be in the market in due time and have essentially narrowed it down to these two options (single vs. double adjustable is a different story). I seem to be in a similar position to blade as this car is my daily (though considerably less miles/day) so I don't want something that will punish me on the streets. So essentially what are the differences and what kind of driving/person do these cater to best?

Harold or others can correct me but my understanding was that the damping force from a monotube shock is generated more quickly. So if you graphed it the line would be more steep with a monotube shock vs a twin tube. On the street it was explaned to me that the twin tube ride would be "better". Here's a decent video from KW showing the twin tube design:

I had TC Klines on my E46 and they were awesome, bought them new from TC Kline. I'm thinking about doing the same on my E90