Wise decision if you ask me. I think TC Kline has been the best kept secret in BMW suspensions and the word is now getting out. The TCKs are very comfortable as long as you match the damper settings to the spring rates. I love the doubles on my E46, there's no doubt that I will be putting the doubles on my E90.
In fact, I've driven my friend's E46 M3 car with the KW Comp suspension in it. Its hard and uncomfortable. On a bumpy track, I think I lost about 1/4" in height it was so hard. And the damper settings are right at the mid mark. It just wears you out.
I just installed the TCK doubles on a friend's E46 M3. SOOOOOO much better. Two E46 M3s...similarly skilled drivers, same NT01s and pretty much the same mods...the TCK car was 1 second faster than the KW car. From the back, the KW car looks jittery and unsettled.
IMO, the TC Klines blow the KWs away as a dual purpose setup. My theory is KW crunches some numbers and the first time the suspension is on a car is when the first customer buys and installs them. Sure, they do a lot of detailed analysis and testing for the OE market like the SLS. I find it hard to believe as a very large manufacturer that they are testing tuner coilovers on each and every car. Maybe they gather data from tuners first but I think the results speak for themselves.
TC Kline has been featured in a couple of different Bimmer Magazine articles (E90 M3 and 135i)...I found it VERY interesting in the article how TCK seemed to start off with a clean sheet on each platform, had the ACTUAL car to test with and addressed shortcomings specific to that car for a dual purpose car.
Yes, I am a TC Kline fanboy. I'm preaching the TC Kline religion.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red