i've got a test pipe, no cat and no res that I can bolt up for the track.
It makes a big difference. Dropped me an average 1 tenth in 1/8 mile times and gained 1 mph in traps, thats with it bolted up to my TRD
alxe back exhaust.
exhaust with testpipe I've gotten close to 2.5mph gains in 1/8 mile traps!!!!!
from 77's to 79's
CEL will come on, it wont hurt anything but the enviornment, so only run it at the track!