I'd rather do it myself
Really no need to sand down the paint if you double up on the ground cable and go to the engine block. The trans, block and heads are all aluminum so they ground themselves.It would be cool to have a list for all body grounding points in both the BK1 and 2 2.0Ts and 3.8s so we could go in and sand down the paint. Any volunteers to make said list, possibly with pictures? Lol
The good ground needs to be to the block as that is where the alternator is grounded and the alternator is the source of voltage when the car is running. All current the alternator puts out must return to the alternator frame.