Well eith my setup, and my daily driving around weight these days is about 8000lbs.
stock=12.8
80hp=8.7
120hp8.5 broke the wheels loose in 1st and 2nd
140hp=8.5 spun wheels on take off.
all were 2wd
and I know they all don't make sense, but it was only 1 run of each on different peices of road. Just did it to give you some ballpark idea...
hope it helps