Headers make a difference?, Headers? "High Flow" cats? some one help! 94 ST Options

[mgnt232]

I Have a 1994 Toyota Celica ST 1.8L 7A-FE
I recently had a Magnaflow "catback" installed.

I was looking into getting headers when i came across something interesting.
I saw that in order for the headers to give you car the extra power, you need to have a high flow catalytic converter. I am not sure if this is true, but i believe it is because the extra flow, from the headers would be slowed by the restrictive stock cat? am i correct? (the cat back is not restricted any more, with my new magnaflow exhaust system)
And if this is correct, would these two things match up?

The cat i am looking at ( http://www.planetmagnaflow.com/mfcatsearch...catmodel=CELICA ) !*The first direct fit one*!

The headers i am looking at ( http://cgi.ebay.com/ebaymotors/ws/eBayISAP...alenotsupported )

Are headers worth it? do i need the new cat? would it be better? with the new cat, is it worth it at all? ive never seen the difference, but im assuming alot of you have, so any one with any info, please give me some answers. thanks!-

[match220]

headers do make a difference in more areas than sound..just to kind of give you an easy technical explanation..stock headers are designed to basically just put the exhaust out of the engine with no science behind it, aftermarket headers do it in a more organized way so it gives you more performance, factoring in exhaust pulse width, thermodynamics and flow equalization. I could type paragraphs on this that would probably bore you with explanations on the science behind it, plus I don't want to type all of it out, but that's the basics. Just stay away from stainless steel aftermarket headers, people usually make a mistake getting those and they don't even know. Stainless steel dissipates too much heat, and when the exhaust cools down, the molecules slow down, which makes them harder to push out of the exhaust system, so it's basically the same thing as having pipes with smaller diameter. This is why people get titanuim exhaust kits, or ceramic coated kits, (cast iron is probably the best thing to get for your money though, it is full of air bubbles that hold in heat in the system) these kits hold the heat in so the exhaust stays hot to the end of the pipes, that makes it easier to push out of the pipes, the faster it gets out, the easier the pistons move up in the engine and the less backpressure you have on your engine. A well designed exhaust system will free up a lot of power in a stock engine, and give a sweet sounding engine, also don't go too large on the exhaust piping. I'm not going to get into that, but it's another mistake people make on N/A 4 cyls, they don't need 3 inch diameter piping!

This post has been edited by match220: Jul 27, 2009 - 2:27 AM