I see all these tuned pipes on the internet, and in the hs, but how do i know which cars they fit? I am probably going to buy a 4-tec, althouh it has a tuned pipe alredy i hear it sucks compared to other pipes. Also, which pipes would you reccomend. Any help would be good.

Thanks

I don't have tuned pipes.....but some guys like the Parris pipe....some like the Cvec pipe...and some like the Dynamite pipe.

http://www.rcnitro.com/rn/articles/tuned.asp

Tuned Pipes come in either .21 or .15/.12 size. Then the header is what fits onto the engine. There are 3 types of exaust that i know of. Rear exaust (used by high performance racing engines) standart exaust (used by most engines) and then Picco exaust which is a round-side exaust made on picco engines. The 4 tech most likely has a standard side exaust. As for a tuned pipe you can try www.rdlogics.com I got the turbo pipe for the RS4 3 and it really really made the car go faster. Gotta be doing another 3-4MPH maybe like 48 now

Here's some really good info on tuned pipes.
http://www.rcnitro.com/rn/articles/tuned.asp

So can I use the header that is already on the engine, or is it only for that pipe?

If you get a 2 piece pipe you can use your current header, a one piece like my RDLogics you have to use the one that comes with it.