Ok guys i am looking to open up my exhaust an i wanted to get some ideas i think i am going to bring it out on the side by the rear tire an how big should i go for the most power

 

You'll loose ground clearance. But 2-1/4 to 2-1/2 is fine you want a little back pressure.

 

Right now mine is just about 12" of pipe after the cat, but am gonna make a side pipe in front of the rear passenger tire with some flex pipe.. Here is what it sounds like with no muffler:

http://www.youtube.com/watch?v=http:...?v=TpPLpI2DH0w

 

so you think 2 1/2 i am having a few peep say 3in but yea i still need back pressure i just wanna do something that gives me a lil bit more should i replace my stock muffler with a new one to

 

I wouldnt go any bigger than 2 1/2... Some people like the sound of a flowmaster on them, I dont. I like glasspacks or no muffler at all but its all up to you, its your jeep..

 

yea i feel ya i am having to replace my cat next week so i figured id open up my exhaust

 

Yeah, might as well do it while your under there.. though I dont really recommend the flex pipe, thats just what im gonna do cause im poor .
If I had the money I would take it down to the Muffler shop and have them run 2 1/2 out from teh cat to in front of the rear tire. Just a side note though, you might get some exhaust fumes inside the cab with a side pipe, especially with the rear window open..

BTW, IIRC the stock exhaust diameter is 2 1/4..

 

isnt the front 2 1/2 where the inlet of the cat is

 

It might be, Im not sure on that..

 

cause i asked for the cat inlet diameter an it was 2 1/2 an the exit was 2 1/8 on the inside

 

Yeah, I dont know much about the cat... Especially for a 98 since mines a 89, but if you got those numbers from a good source then thats what I would go with..