...In order to run anything more than 7-or-8 PSI reliably and without detonation you are going to HAVE TO lower the stock compression ratio in the M3's motor (10.5 to 1). Even with proper tuning.
...You can buy Active Autowerks 1.5mm headgasket which will bring it down about 3/4 of a point and allow you an extra 2-to-3 PSI or so pounds of boost safely (to make for a total of 9-to-11 PSI max.) But to truly achieve over 450+HP you're going to need a larger CR reduction...refer to my post in this section about Rob Green Motorsports "Shim kit"
--- K. Davidson