I did a search and found people talking about the JRSC and exhaust setups as I'm trying to tweek the most out of the JRSC when it comes in as possible. The only peice I have left to replace is the flex pipe. Is it true that the JRSC needs some back pressure to perform at it's best? Also, should I even bother buying that flex pipe. I wouldn't think that it would make that much difference, but I could be wrong. Thanks in advance!

What size Exh did you go to ?

If the ID in the flex is smaller than you smallest ID in the system than that is your restriction , All FI likes to breath a 3 inch wouldnt hurt a thing

Tom

I have the OBX header and downpipe and a borla cat-back 2.5". All FI likes to breathe 3"? Even at 9-10 PSI

You need to watch the cat back systems , about all of the 2.5`s that i have seen shrink down to 2 1/4 right at the muffler , this means your 2.5 system is 2 1/4 if you beleive that the Exh system is only as big as your smallest Inside Diameter

I would go with the SVT header , Still in my opinion the best header on the market for the Focus even the ZX3 Zetec

Tom

I will look into getting that header. I'll need the high flow cat for emissions early next year, so i'll probably be thinking about that when it's time to "get legal". I've also bought the TB, SVT SRI, plug wires and I'll buy some colder plugs too. I bought the kit from Steeda if that makes any difference. I still can't find a flex pipe that's 2.5". The ones i've seen are all 2 1/4.