To the OP,
I have a 2008 M3. It's a 6 speed with ~65k on the odo. Stock clutch and flywheel. This will be two 2 years with Active's Level 2 kit running Meth. Car is still running strong.
Some of my recommendations if you go the supercharger route:
-Don't spend money on larger wheels like I did. I had ADV5.1 20"...they looked great, but were very heavy. Over a year ago, I switched over to TE 37 SL's 18" and I love them. Couldn't be happier. It was a noticeable difference. Plus they fit my Stop Tech Trophy BBK. You don't really need brakes if all you intend to do is drive on the street, HOWEVER it's a nice upgrade because the car will hit significant speeds before you know it once it's boosted.
-If you go suspension, I've been pretty happy with the KW V3's plus they provided a nice drop between the tire and wheel well. The Club Sports in my opinion were too hard for a daily drive.
-Since you have a 6 speed, you should put a short shift kit on there if you don't have one. I have Active's and the throws are significantly shorter, however there is still a slight rubbery feel to it but a vast improvement over stock.
-A must have if you go FI, would be a full exhaust with high flow cats. I'm running a full Active exhaust with high flow cats and the car sounds like an exotic to me.
- I have STRI gauges: water temp, boost, & oil pressure. Nice to have, but not necessary.
-Engine Ice Coolant...I live in South Florida so it gets pretty hot here in the summer. Not really a significant change versus stock, however I do notice that my water temp doesn't warm up as fast. Again not really necessary.
-Be prepared to swap out your rear tires more often. The tires I used to run were the Re-11's...really handled well in the dry and the rain. Would of stayed with them, but Bridgestone had a 6 month back order on them so I switched over to the Michelin Pilot SS. I have close to 9k miles on the tires and will say the tire tread wear seems to be holding well. Compared to the RE-11's they seem to be just as sticky on the road. I'm very happy with them.
My last bit of advice is if you plan on keeping the car for a long time; plan on doing an engine re-build. That's what I am currently pondering. In my opinion it doesn't matter what brand of supercharger you use...the bottom line is the M3 wasn't made to be boosted. Sooner or later things break. I'm leaning more and more on the side of keeping the car for a very long time. There's no other platform I can think of that is as good as the M3 for a daily driver. Well maybe a GT-R, but it doesn't come in a stick. Throw in all the go fast parts like suspension, brakes, wheels, tires, etc, and a supercharger... you'll have an unsurpassed platform that not many can touch.
As others have mentioned, if you go the FI route, whatever manufacture you go with, make sure they have great support because undeniably there will always be a time when something is off. Hope this helps in your decision.