I want to put an aftermarket header and a cat on my car with the same stock catback pipes. Would that be a good idea to or should I get new and thicker pipes and if so where can I get it from without buy a catback.

 

Why??
You can go ahead and do this, but a few things:
You aren't going to notice as much of a HP increase since the exhaust flow will still be slowed down by the stock muffler.
Replacing the cat. with an aftermarket or 'test pipe' type will make your exhaust louder for sure, with the stock muffler though I'm not sure how much.

 

Excuse my error but I meant to say is that I have an aftermarket muffler, cat, and a header with a down pipe. Would it be a good idea to keep the stock pipes from the catback and will I ruin anything in the engine from that.

 

you probably wont ruin anything but you wont get the best possible flow.. not that exhausts give you that much hp anyway.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackmfoggie &raquo;</TD></TR><TR><TD CLASS="quote">Excuse my error but I meant to say is that I have an aftermarket muffler, cat, and a header with a down pipe. Would it be a good idea to keep the stock pipes from the catback and will I ruin anything in the engine from that.</TD></TR></TABLE>
even with that stuff, if you keep the stock pipes it will still restrict the flow and you wont have the power gains you would have with aftermarket piping.

 

Where can I get the pipes from without changin the catback

 

any mail order catalog that sells aftermarket **** should have stainless steel tubing. Or you can go to your local steel mill/yard, they might sell you overstock.