I have high flow cats n love em. If you found old 2005 threads, a lot of people had high flow cats or no cats. Everybody loved them except for the environmentalist. 3" isn't that a lot bigger than recommended size.
new engine,1.7 rocker arms,Pipes exhaust, shorty cats , shorty headers,under drive and overdrive pulleys,4.2 upper plenum, throttle body spacer, cold air intake, stage one clutch, shorty shifter, and tune. 8.8 in storage