See I hear differing views from the US. The 370z seems to respond really well to breathing mods, giving a good slug of HP and torque throughout the rev range (~20HP from intake or exhaust, havent seen conslusive numbers for both combined). Those that have then tried to use UpRev to improve it, have found only minimal gains over the OEM map, which seems to suggest the OEM map does rather well with itself. However those with no mods seem to release about 15-20hp from having UpRev just adjust the AFRs and I beleive a tweak to the timing. Have UpRev cracked the VVEL yet? (or anyone for that matter?)
We'll move this to another thread if you have some juicy info