although nathan's is good for some people (shuddup kevin, i dont want to hear your bitching), it is un-intercooled (meth injection could take car of that though), it is for Splitport heads (wont just bolt up), and wont fit under your stock hood (not sure if thats a big deal for you). now im not knockin' Nate's kit, it's just not for everyone.
for your case, i'd say do a M90 supercoupe swap, along with ported heads and cam (if money permits).
you'd have plenty of power for driving everyday (and make gobs more torque than the M112), they run an intercooler, and get the same supercharger whine as the M112.