Im increasing my exhaust from 2" to 2-1/2". Im thinking i will use 3" glasspacks instead of 2-1/2" because of resistance. Pros - Cons?

 

Typically any time you change pipe size flow suffers. You want one size the whole way for best flow. I like to match it to the collector size, and place the mufflers or glasspacks as far back as possible. Therefore, I'd use 2.5" glasspacks. Get the shortest ones you can get for best flow.

Better yet, who needs 'em? Just run pipes out the back!

 

im running hooker headers, i bought the conical offsets to get me bellow the cross over. im making a H pipe .then to the glass packs ...then out the back.

 

i wouldn't worry about resistance with a glasspack muffler. they are a straight through design.

 

Exhaust work is a pain...

I wish you luck! Sounds like the good plan.