I changed that Golf's setup totally, but I think that time was the one with 2006 Golf GTI 2.0l turbo FWD powertrain with about 160kW, everything except weight reduction maxed from suspension/brakes/gearbox and sports tires. No downforce at all, I thought it'd only slow my car down as its not very powerful in the first place.
Now I'm driving the same Golf mk2 GTI with original powertrain with about 130kW. I have everything upgraded from suspension/brakes/gearbox/weightreduction/etc and run it on widened racing slicks with no downforce. It only weighs 810kg so its pretty damn fast round the bends. 8) Still does +200kmh on the main straight though.
edit: the low-weight mk2 GTI is doing well under 1:01.500 times atm.
edit2: forgot to mention about the tuning setups, I only softened the suspension (springs,dampers,stabilizers), optimized the gear ratios (on the limiter just before braking to the first bend) and changed the LSD to 5%. I'm fine tuning the setup constantly but thats it roughly.