Apparently the ESS supercharger is good for 240rwkw on a healthy 330ci, which will beat a stock m3 (170-180rwkw)
I have not done it or seen it, but I've read it on here. Apparently its around 12k installed and tuned, but it will not help your resale much at all. The car will still be worth a lot less than a clean m3, not to mention illegal.
Last edited by Scotty_89; 11-09-2012 at 08:54 PM.