I knew they cost around £1400 with the ECU kit, ...but i was lucky that Aylesbury had a pair lying around they did me for £600, ..don't ask me how why what, ..i just know i a) was in the right place at the right time, and b) must have spent enough that they thought i deserved it.
...if it is just noise you are after loosen all of your bolts and wedge a coke can in your exhaust