Hi ive got a 2004 a3 2.0 tdi 140 sport and i need to change the rear discs and pads and give it a service. My dad has bought the right caliper wind back tool but do you need a special tool for the sump plug or is it a normal bolt?. Also we are not sure what size discs to get as it comes up with two different sizes for the 2.0 tdi. and finaly what oil should i be using. Thanks in advance if anyone can help. Pete.