I was talking with some people about this recently and wasnt too happy about what i heard. I have a 98 TA with dynomax cat back and stock headers/cats. One of the pipes under the driver side is actually oval. Anyway to get to the point, they said that if i made that pipe circlular + got high flow cats and or long tubed headers that clearance on my car would be VERY bad and that when i went over a small bump or anything it would hit and damage the pipes and cats badly or destroy them.

Is this true or how have you dealt with it?

Any input would be much appreciated, hope this was clear. If not feel free to ask questions.

 

That's how the T/A's come stock. If you look down the entire exhaust clear to the muffler, you'll see a couple of "weird" spots.

Clearance shouldn't be a problem with new LT's/Y-pipe. You gotta be careful of course. You will lose some clearance, but it's not like you had a ton to start with.

 

Yea, they come stock like that. Im asking if i actually fix that and make it circular if it will cause clearance problems for everyday driving.

 

many, many people on htis board have long tubes and "circular" y pipes and have no issue with clearance. If you decide to lower the car the CAN be issues. But there are a lot of people with long tubes and are lowered.
Hope this helps

 

As long as your car is not lowered you should be fine.
I have the Eibach Pro kit on my 01, it's lowered aprox 1.25".
Here is my oem Ypipe:
http://nick.vettextc.net/Ypipe/OEMYclr.jpg
Here is ground clearance with long tube headers and a 3" ORY:
http://nick.vettextc.net/Ypipe/TSPORYclr.jpg

I went from 3.25" down to 2.5", so I lost 3/4" going from the oem oval to a 3" round. The common problem people have with 3" aftermarket Y pipes is with clearance between the pipe and under the car causing banging which in turn can result in false knock.
http://nick.vettextc.net/Ypipe/TSPy004.jpg
Alot of guys here have come up with ways to help fix that so don't let it scare you away from putting headers on your car.