I have driven non rev up before. I can tell you it did feel slower than the rev.up.

Also, mod way, there's not that much you can do for s2k besides FI.

There's not that much you can do with G35 too, but there's more you can do to get power than s2k. MD MREV2=15whp minimum. Dono how much exhaust and intake gives, (i highly doubt it gives more than 1-10 to the wheels)