[esnow1]

want to upgrade my exhaust system on my 2010 Elantra Touring SE 2.0,  I already have a magnaflow muffler for it, but what size pipe should I go with, 2.25 or 2.50, or is 2.50 to large, let me know, thanks

[Phil №❶]

Does your car have extractors o headers

Remember that for any increase in diameter there is a squared increase in internal volume, so 2.5 is better for gas flow than 2.25. However, exhausts should be properly tuned to achieve the most efficient flow, it's not just a simple matter of increasing the pipe size. Be aware of ground clearance, too.

[Dazzler]

Good point about the ground clearance too Phil... 

2 1/4 inch is what I'd stick with, unless you are doing head work you'll lose to much back pressure.

Upgrading the mufflers and catalytic converter to free flowing should be quite sufficient - even with extractors.

Not sure what the standard size of your exhaust already is ( mine is 2 1/4 standard ) if your lucky it's already 2 1/4 and you only require upgraded mufflers and Cat.

As Phil mentioned ground clearance is a concern to be aware of but a good installer will be able to keep it tucked up out of the way like the standard exhaust.

[Doggie 1]

I've always found 2 1/4 inches to be adequate. 

You've got to be happy with what you have