Assuming we're all running Street Tire, here's the STU vs. NESP vs. NSM break down:
STU:
+ No brake restrictions
- highest PAX (.81

- Cat required in exhaust
NESP:
+ lowest PAX (.800)
+ Intercooler mods allowed
+ Unrestricted Exhaust
- No brake mods outside of pads/fluid (I think this mean no SS lines!)
NSM:
+ No brake restrictions
+ Intercooler mods allowed
++ Boost mods allowed
++ Hell, just about every mod, 'cept the ALK allowed!
- Cat required in exhaust
- middle PAX (.815)
So, assuming I'm not missing anything... if you have the money to build up a SM car, you should clean up in PAX this year. Of the alternatives, NESP >> STU... but if you've done SS lines, you might be screwed... we need to double check on the brake rules for SP. But if SS lines aren't allowed, and I already had 'em on my STi, I'd just get a reflash and run in SM.
And anyone w/o a cat planning to run SM (*cough* Mike), you might want to look into getting a flanged cat insert that you can toss in the car for race days, because the alternative (E-Modified) doesn't seem too good.
