Celica Forums General Discussion Exterior What size piping?

I am going to do custom piping from either the axle, or catalytic converter back. What do ya'll suggest i do and what size piping should i use.

stock piping is 2.25" or 2.5"

It's one of the two, either way you'll be good to go. I wouldn't go any larger than that unless you're getting forced induction because you want to keep the exhaust gases hot. I'm not an expert or anything but i know that that the hotter the exhaust gases, the faster it moves which is what you want in a custom exhaust.

I have new piping right before the CAT and all the way to axel..
CAT has been replaced with high flow cat and resonator is gone...
But warning this setup will be loud...
Oh yea.. it's all 2.5"

Yup, very loud. Illegal loud. If you aren't scared of the pigs then go for it.

Sooooooo if i have 2.5 inch and go to a 2.25 inch pipe, will it improve the flow of my exhaust? And how would this affect the sound?

2.5 That would be my reccomendation. The only reason being that it'll make whomever welding the pipes a whole lot happier because it would make the weld easier. And if you buy an aftermaket muffler, i'm almost 100% sure that they most commonly come in 2.5 Diameters!
Happy Exhaustion!