how would i do this?
 

I have a 01 silverado z71 with true dual glasspacks....I've been looking around and i've heard a few good things about runnin x-pipe underneath but i don't know where i would weld that up at? Would i weld it up in the middle of the cats and the glasspacks? Also i'm goin to add some longtube headers to go along with it.

After the cats, before the 'packs... You could also do an H-Pipe, cheaper and easier, but not quite as beneficial.

would i just order the x pipe from magnaflow and cut out some of my pipin and replace it with the x pipe? or would i have to re-do the whole pipin underneath

I don't know... It has to be welded, I know that. I'd have to see your set-up in person.

Its true dual....got pipes runnin from each header all the way to the back where it meets the glasspacks then run out the back at a 45 degree angle


http://www.magnaflow.com/02product/s...e=main&id=8487

check the link:
http://www.spintechmufflers.com/x-pi...s/cat_126.html hope this helps

from what i've read it does have some performance benefits...but is it even worth it?

yes it does. it will help the exhaust flow from both cylinder banks. i would put it in just behind your trans X member.

is that one from magnaflow a top choice or is there something better?