After driving it for a few days, im going back tomorrow to have the 3rd Cat put back in. The car doesnt feel the same, plus I am having some kind of rattling coming from under there.

 

hm, if you saw an increase in performance why not try a bigger resonator to kill the sound?

 

So all in all, would you say a custom J pipe is worth getting?

I have the SC and e-shift pro cats. Currently in the process of doing a 2.5" straight pipe exhaust for the track. Basically it's just a straight pipe after the J pipe to the back of the car, 2.5" all the way through. I was going to go with 3", but a few exhaust experts have told me that 3.0" is too big for the TL considering the SC is only running at low boost.

Now I am deciding if I should do the J pipe as well.