small things like changing spark plugs, fitting a CAI etc i'll do on my own
servicing is left to my Audi dealer, for resale value (tho i have no intention of selling my car before it dies anymore) and because they give good will contributions for out of warranty claims with a full service history. it needn't be expensive - if i provide my own oil they charge me less than £100 for a minor service
aftermarket stuff was previously done by Midland VW. whilst i think they're a great bunch, i have now gone with vRSAlex and his firm AKS Tuning. you can't beat a specialist who owns a car with the same chassis and engine as yours and he is an absolute perfectionist in everything he does.