ok to start things off...the guy at the exhaust shop said that if I put a test pipe on my car I would have no back pressure and would fry my engine and ecu. I heard he told me this cause he didnt wanna get a ticket for making me one or sumtin like that .I have no idea whether this is true or not so i figure I will ask yall. I dont get the concept of back pressure really, but I really want a test pipe on the car to open it up a little bit more, what do yall think...oh and where can I get one I didnt see wsp's ont here site, I looked like 4 times.

 

It will not hurt the car, but the gain is around 1HP.
If you have a fully functional cat you should just leave it.
If your wanting to open up the exhaust get the Y pipe and an exhaust setup.

 

stick with the cat...its going to smell like sh*t all the time if you go with the test pipe. did you get a ypipe already? bpipe? etc?

 

yeah I already have a 2.5" b-pipe with apexi N1 muffler

 

backpressure is always bad, but maintaining a high exhaust velocity is very important. A cat does both. I have a test pipe, but I'm replacing it with a high-flow cat when I get a chance to. Not having cat will not fry your ecu (that is just stupid), but it really isn't worth getting a cat replacement. Also, then you have problems with your rear o2 sensor, like I do

If you want power, get a y-pipe.

 

they can get a hefty epa fine for removing int so that sounds like it makes sense as far as him saying something. Wont affect your ecu at all, but you can easily just purchase an o2 simulator if you decide to go that route, i wouldnt recommend it but some people are hardheaded.

 

I just busted my high flow cat up. It was rattling and falling apart inside so.. Seems to flow air really nice now, though I have not had the chance to drive it yet. I don't have any o2 sensor past my y-pipe so I don't see any problems. I hope it don't smell like a$$ but im pushing more air so it should be ok. Didn't smell bad at idle. Sounds good, not any louder.

 

Running with a hollowed cat is actually not as free flowing as you would think.
The exhaust doesnt flow straight throiugh, it bounces around in the hollowed cat before exiting and can actually hurt your performance by becoming a bit more restrictive, not to mention its louder.
Im sure it will be much louder for you under a load or at WOT since your boosted.
I drove with my holllowed cat for a couple of weeks and hated it. The car was definatly louder and it did seem a bit sluggish.

 

Leave the cat and get a y-pipe.

 

First off, find a new muffler shop cause lazy old Fred Sanford don't want to work, second fry an ecu because of no cat?? Did he say the flux capacitor was going bad too?