I went through this last year when I re-did my exhaust. I was looking at 2.5 or 3" and Aluminized or Stainless...I decided with 2.5 Aluminized. Not because of cost factor but because the sound of the pipe and clearance under the car.

I was quoted (converted from Euros) $650 for 2.5" Stainless. The problem with the stainless is that the wall thickness is super thin so it is going to resonate much more.

I put 1/2" Stainless flanges on my exhaust because I may want to disconnect portions down the line to remove the trans lets say. Why Aluminized and not SS? Who is going to crawl under my car to see something I paid so much for? I had 12 yrs on the last system and it didnt oxidize or discolor.

I think 3" is overkill. Thats just me....I have 2 1/2" pipes into Flowmaster 70 series mufflers (Diesel).

What will you run H or X pipe? That was what I battled more with than anything on the work....I went with an H but I also installed exhaust cutouts and it SURE IS FUN!!

Can't say about Alum vs. SS, but TTI tech said when I bought my system that 2.5" was plenty enough for 500HP or less. The 3" system I have looks bad-ass under there, and even though it fits really well, it does occupy a lot of space, and clearances are minimal. Springs, tank, shocks, and brake hose are factory located ('72 RR). In retrospect, 2.5" would probably have been better.

BTW, wife's '09 Toyota has factory mandrel bent exhaust, so there must be something to it.

I bought the TTI 3" X-pipe system out to the rear bumper. Car has stock gas tank and wheelwells and it fits fine. I went with 3" as I knew my new eng was going to be close to 600 hp and I race it capped up. Ron

I'm wanting the "X" pipe. Truth is I really dont know witch one would be better, I just like the look of the X
Spoke with the shop owner and he said if I post that his shop did my exhaust system, he would do the job for $1,100 out the door. 3" Mandrel bent Stainless with Custom Stainless Mufflers too.
No special tips, just turned down at the bumper.
I think thats hard to beat considering not having to do any work other than opening my wallet

that price is crazy..

For you guys that think (know) the price is high. Try pricing it locally for yourself. And for us too
Apples to Apples; Header to bumper in 3" SS Mandrel bent with SS mufflers installed.
First, few shops have Mandrel Bending Equipment and even with standard bending, their prices are not much cheaper if at all.
Let us hear your legit quotes.
What does bother me is that someone mention that the SS may be noisier than with the Aluminized pipe
That would SUCK!

I built my own 3" on my Charger with an X pipe all the way to the rear bumper with Flowbastard mufflers. I have less then $300.00 into mine including the mufflers. As all the local exhaust shops told me. Throughout an 8-10 hour day they could do up to 15 cat back or exhaust repairs ob different cars at several hundred dollars each or a custom like my car would tie up a hoist all day so $600.00-1000.00 was the going rate. Sorry no pics. Here is the finished product out the rear thru the stock tips.

you must have gotten the "Flowbastard mufflers" on sale!
Good for you man.
I've priced it and theres no way around here for even twice that!

I would only go 3" if the engine is over 550 HP, or it is a race car. The 3" will be louder than the 2-1/2" if using the same type mufflers. The mandrel bent exhaust does flow way better than the standard crimped bends. The rest comes down to cost and looks. Stainless should last longer and can be polished up for a show car, but is more expensive than the aluminized exhaust. Custom bent would be best if the person does a good job, but this again usually is more expensive than buying a kit off the shelf.

I went 3" with a mild 413 in my challenger, simply because it didn't cost that much more over 2.5 and would be one less thing to change when I go more motor.

Far as price, hard to beat the systems jegs/summit sells, which are for headers, not sure which you'd need.

I have aluminumized on my cummins, 2 winters with lots of salt, no rust even showing on it yet.

I went with the 3" stainless, X pipe and mufflers all from Magnaflow. It fits and no rattles but it is tight in places. I also installed four stainless mufflers and it is still pretty loud. I also installed two turbo style stainless clamps on the pipes where the turn up to go over the differential. These clamps are reuseable and easy to remove. Remove the clamps and the tailpipes and rear mufflers come out. Unbolt the header collectors and the entire exhaust system is out in less than ten minutes.

Here's a few pictures.

Pic 2

The fuel tank was custom built for this one but a stock tank would fit here with no problems.

Nice! Thats what I needed to see, WELL DONE!

I don't think I have room for multiple mufflers and I don't want it to be too loud. Options? Are stainless mufflers louder than others typically?

Being SS has no bearing on sound.It just depends on the muffler type.I have Summits 3 inch SS on the 65.Exits in front of the wheels.Just has a deep throaty sound.Been on for 8 years and still look great.If I went all the way out back it would be quieter.I believe you can run 2 1/2 out the back with springs moved in.3 inch I dont believe will fit unless the tank is narrowed.Rocky

curious, has anyone weighed a 2.5" system over a 3" system?

As was stated already, I don't think the material the muffler is made from determines how loud it is. The muffler design has the biggest effect on how loud they are. In my case, both styles of mufflers I used are very low restriction units. If you hold them up and look through one end you can see directly out the other end. That was the main reason I installed two on each pipe.

1) As it has been stated; a good 2.5" system will support over 500hp without issue.

2) yes mandrel bends matter

3) and exhaust system is a SYSTEM and many/most people underestimate the importance of muffler choice; the difference between a crappy flowing muffler like a Flowmaster and a good one like a Dynomax Ultra-Flow is HUGE.

3" pro's
- all other things being equal (mufflers, mandrel bends) then the 3" has room to grow if you want 600 or 700hp later.


3" cons
- price
- space restrictions (like the fuel cell note above) can make install and working on nearby components more difficult.



Dave