Hello Jamie and the OP check out Car Parts, Spares & Accessories | Car Parts UK | Buy Car Parts Online | Buy Parts By for clutch prices .
The clutch and flywheel for our 3.0 TDI B8 is £506 delivered. Genuine LUK parts. I don't believe there are any other manufacturers for these at the moment. LUK make them OE for Audi, there don't appear to be any uprated parts available although I have seen a few in Europe running standard clutches and over 650Nm .
What year is your a4?? Would mine be the same as yours?