I have a ba xt with a cold air intake and have just got given an f6 typhoon exhaust and looking at buying extractors all the ones on eBay look like they are to long to suit the cat do I have to get an aftermarket exhaust system to suit

It will be fine. When you get the extractors installed, you will need to make up some extra pipe to reach down to the cat.

Ohk sweet as the ones I am currently wining are stainless so I think that's gonna be a bit of a pain