You can buy any amount of crap on e-bay for your A3 from VCDS leads that don't work to roof spoilers that do not fit. another thread today is moaning about e-bay S-Line badges that corrode. Wafer thin carbon sticky sheet that just wears through, lamin-x that falls off, cheap copy wheels with doubtful safety, Crap after market mats and LED kits that don't work..
The lesson here is if you want Vauxhall quality buy a vauxhall, if you want Audi quality buy Audi. Buy a proper VCDS lead and register it and apart from Nige here who is a mine of info if you have a genuine lead, you also get access to Ross techs technical guys. the lead/software will be updated as and when and when you sell your car there are any number of people willing to buy your proper lead back so the real cost might only be £50.
It never ceases to amaze me the amount of people who will buy flash wheels , coilovers, new front ends, led rear lights etc but throw their hands up at the thought of buying something useful..