My 2001 GT has 105,000 miles on it and is need need of new mufflers. I plan on replacing the whole cat back system as the resonator is pretty rusted and will most likely eventually go as well.

Here is the problem and question. My stock Grand Prix has mandrel bent pipes. I plan on replacing everything with Walker OEM parts but the bends are not mandrel they are the bent bends with the ridges. Will this make a difference in performance? Should I even worry about this?

Also, Advance Auto'* website says the Walker part fits but does not give the inside or outside diameter of the pipe. Does anyone know the diameter? Part #55204 I need to buy clamps for all the pieces as I intend to do the work myself and do not have a welder or even know how to use one.

I've been looking for the least expensive option and have found it with the Walker system. I have to buy all the parts separately on Advanceauto'* website but will be around $310 w/o tax for (2) mufflers, y-pipe, and resonator. I will need to buy clamps and such and refinish my existing tips if I can. The least expensive "cat back" system that would fit according to multiple auto sites was a magnaflow which was over $800. The magnaflow is 2.5" pipe however. I still cannot find a pipe size for the Walker. It may be 2.25" - will this make a difference compared to 2.5" mandrel pipe?

UPDATE...

I just received a quote from Cole Muffler & Brake for an AP catback system w/o tips. They have all 2 1/4" pipe, mandrel bends and will clamp everything together. The resonator and muffler have a lifetime warranty and the pipes are one year. The total for parts and installation was $395. If I wanted to buy the parts only from them it would be $365 but no warranty on any of the items.

Just to get a comparison I called Monro Muffler & Brake and they had the exact same system w/o tips installed for $907!

Anyone know why Cole can get and install for so cheap????

Shoot... One thing I didn't ask is what style the system components were. I'm assuming they will give me the cheapest stuff AP has. Will it be any good and hold up to WNY winters?

Any suggestions?

are your mufflers and stock piping rusting as well or just the res?

My mufflers are completely shot. They both have large rectangular holes in them. The resonator is rusting and the welded seams are a little wavy - I'm assuming it will break apart at some point. The pipes are rusty but they seem to be okay - no holes that I can tell.

What type do you suggest - AP or Walker? How will each hold up?

Thanks.

So long as its aluminized steel, you should be ok. Rust is rust, and nothing but stainless steel will be completely rust-proof.

I was told my current stock exhaust system is stainless and it is rusted. It is 9 years old however.

I will get back to you shortly. I will ask my boss at work. I work part time at an exhaust shop, btw both of those quotes seem high to me. But I'm located in Southern Illinois, big difference I suppose, lol.

What your car again?

Stock exhausts aren't stainless, unless I'm really missing something huge here. Stainless is not easy to bend, requires TIG welding, and is a lot more expensive. GM wouldn't have gone out of their way to put stainless exhausts on these cars, trust me. We have cast iron front exhaust manifolds...

We don't use Apex in my area, but the Walker should be a good stock replacement. Same size piping and I wouldn't worry too much about the bends.

If you are concerned with rust, perhaps you should coat the exhaust in spots and see how they hold up over time against the normal piping. On my exhaust I used some por-15 on my welds and they have been holding up great. Just a thought.

Another thought is if your piping is holding up still, replace the resonator with a cheap glasspack and order some walker factory replacement mufflers so you still retain a stock sound.

Pics would be nice, but I know thats not really easily done. lol. If you trust the shop employees, go with what they say. I work for a father-son shop, we'd rather see our repeat customers happy but I can't say much for the bigger shops. I have never seen a 900 dollar exhaust job in our shop unless it involved manifold replacement or some really expensive corsa or borla kits.

As far as stainless goes, my TOGs and downpipe are stainless. They don't rust. I do know of a used borla catback for sale local in St.louis for 500$. Thats not me trying to sell anything (it'* not mine or a friends) but they run 1000$ new and are stainless. I can contact the owner for you with your info if youre interested.

Feel free to pm me or ask everyone here any other concerns you have.

ignore my post about asking what your car is, thought someone else was asking.