I'm not sure what I'm putting to the wheel now since I have my headers. Before that I was running GTM Resonated Test Pipes and put down 322 rwhp and 257rwtq. And I'm running an underdrive overdrive setup from NST. Not sure how much more power it gave me but there is much more throttle response and no lag from a dead stop at low RPMs.
If you are talking about the leather ones in the car they are katzkin seat covers. You can go to any automotive upholstery shop and they can order them for you in any way you like.