They're both the same pipes, the non-catted needs an updated tune to remove the rear O2 sensors from the ECM checking so you don't get a light.
All catted pipes except PPE (from users experience) set off a CEL unless rear O2 are tuned out, the PPE pass emissions and readiness checks.
There's about 2-3HP difference between catted and non-catted and the PPE cats stopped the "stink" from my stock cats in the car under WOT.
They're fairly easy to install on a lift, on the ground it's a PITA.
I'm having a post xmas special pricing on PPE pipes:
$565+ shipping for PPE catless
$885+ shipping for PPE catted pipes