new exhaust question

hey guys, been looking at doing cat-back system, and have decided to go ahead and change out everything except the manifolds. just a few questions

is the one that they sell at pfyc legal/will it set off my o2 sensor.

in plans to keep it relatively stock as a whole, how much bigger pipes can i put on the car without running into problems.

not sure about flowmaster, dynomax, or borla yet, but think i will just buy the muffs and put them on , so new resonator or no resonator?

lastly which is better? aluminized steel, stainless steel, or aluminun 100%

also if anybody has other info that might be helpful, feel free to pipe in, all input is appreciated!!!

TIA!!!!!!!!!

Well if your going to do from the mnflds back you must be talking about getting the RAT DP,then yes your o2 sensor will fit and the piece with the cat is legal ,go with the 3" dp ,for the cat back you have many choices and they are all good ,stainless is the best,next is aluminized steel then plain uncoated steel (which is what most exhaust shops use) you ca'nt get 100% aluminum pipeing for exhaust,the stainless will last the life of the car but is more expensive ,a good choice would be the GM stainless cat back around $500 I think.

3" dp is a good idea, as far as muffs i'd go with the flowmasters. If you get flowmasters someone on hear told me to go to ebay, seller is performance peddler and they only cost 45$ a piece, I had no problems gettign mine

Depending upon what pipe size and model (e.g. Delta or Super 40).

just get rid of the cat and get the o2 simulator. you'll be completely new all the way back from the engine

The stock cat isn't all that restrictive. The DP and the Ubend are the weak spots. Please don't remove the stock cat for that 1 hp gain (if you want more flow get an aftermarket high flow cat. You'll never notice the difference between stock cat removed and straight pipes or stock cat and an after cat exhaust. besides it's against the law if you plan on keeping it street legal.

100% agree with Herc. The old philosophy of "cat is very restrictive" no longer applies with newer cars. If there is still any doubt, check out the dyno runs done by Thrasher in their exhaust backpressure study.

http://www.thrashercharged.com/tech_htm/exhaust.shtm.

Noticed you are going to add atranny cooler. Save your money. Check out info on zzperformance.com. These guys know their stuff.

already heard that about the tranny cooler, but if you look back at previous posts, you'll know why the tranny cooler is needed on my particular car
herc, didn't plan to need to change out the cat, but i figured that if the DP and U are going to be changed, it would be cheaper to just buy the one off PFYC, and change out the cat in the process, i wasn't going to do anything soon, just was under changing fuel filter, and noticed that i am in need of new pipe/muffs, cause there is rust creating leaks holes in muffs (great roads we have here), and soon to be in pipe (or at least looks that way)