so Im going to do a full exhaust system. all maggies. rip out all 4 cats, replace with 2 high-flows. true duals to an x-pipe then to a di/do muffler. heres my choices:

5"x11" (which is 22" long and 5.75" wide?: http://www.magnaflow.com/02product/s...e=main&id=8196 )

then theres:
5"x8" (which is 18"x4"?: http://www.magnaflow.com/02product/s...e=main&id=8195 )

or even the
4"x9" http://www.magnaflow.com/02product/s...e=main&id=7969

and then dumped after the avle for drone and whatever.

my question is: which would balance the quietness and performance? I know that high-flow cats(2) will make it much louder than the stock or even 4 hi-flo cats. I also want it so when I punch it she really tears open and eats small children...ideas?

 

I don't think you need and x becuase I think the di/do have an x inside if I am not mistaken. Someone may know for sure.

 

hmmm I read elsewhere that the di/do has an x-pipe intergrated...intresting. so on the size of it? its going to be 2.5" all around so I dont have to deal with different sizes.

 

This is correct. Your best off going X pipe with two SI/SO mufflers for best performance.

 

so...190 for di/do or 175x2= 350 for 2 si/so? might save me some, worth the $ for di/do. but how much gain in power would I get from 2 si/so over the di/do?

 

A little better low end torque with the X pipe mounted where the original Y was for best scavenging.

 

low end huh? but either way I would gain a lot more over stock right? and it will breathe easier

 

Maybe with 2.25", with 2.5" true duals you may suffer low end a little like I did, but high end power is excellent.

 

why 2.25" isnt the stock piping 2.5"? or is it 2.25" to a Y pipe then 2.5" all the way out?

 

Well yeah, but you said DI/DO which means dual pipes per bank, which isn't healthy on these trucks unless its done in 2.25".

 

whys that? please send me the science lol

 

Basically, the 2.25" allows you to keep your low end, but the sound is not as rich as it would be with 2.5" piping. Now if you are set on true duals, then go for it, but understand you may lose some low-end performance. It's a trade off: sound vs. performance. Like Darren said if you do a lot of highway driving and little to know towing, 2.5" true duals could work well. Just keep in mind the piping sizes effect how well your truck will perform at various rpm ranges as we both stated. Another option is a typical si/do which you could do with 2.5" piping and not worry about losing low-end. It all depends on what you want sound wise and what you want to fit your needs.

 

would I gain more top end with 2.5s?

 

Most likely.

 

hmmm top and sound or bottom w/ perf, hard choice