I wish I'd seen this earlier. I've done 4 autox's with my golf, two on stock suspension, one on just rear springs because I didn't have the chance to install the fronts yet, and one on lowered springs all around. All of the autox's were post APR Stage 1 and with stock tires (195/65R15 all seasons).
The first two were on a very tight course, where 40mph is the max you would ever think of reaching, and I got the fastest time of the day on both, roughly 3 seconds faster than the next fastest which was a group of miatas. It's almost scary how well this car does in tight courses, but I imagine that would apply a bit less with the wagon.
The next two were on more open courses where just over 70mph is the fastest I hit. I'd say the first time with just the rear springs replaced was the better of the two, and amazingly fun. The car handled the slaloms like nothing else, and really transformed my idea about how rear suspension should be setup. It was amazing. The second time with both front and rear springs was filled with a bit more understeer, and I don't know if it was any faster. It is when I decided I desperately needed a rear sway bar. Both of the times on the faster course I placed around mid pack, a few seconds behind the STI's.
The way I autox is not for the competition, just for the fun of driving. Neither of the events had any rules about mods, and any winning was entirely bragging rights, which is what I find the most fun.
Thinking back it seems like I did everything entirely backwards, where the first mod to my car was massively increase the power, then I slowly began to think about improving the handling, but this car handles that increase in power astonishingly well. It really felt like the increase in power helped my time even in the super tight course. Another point to be made, I think the stock steelies with super high profile tires is probably the fastest combination in a super tight course such as with my first 2 autox's. I weighed the setup when I switched to my current setup, and the steelie setup was 4.5lbs lighter per wheel, even with my crazy light Enkie rpf1's. If you can find performance or summer tires that will fit on the OEM steel wheels or other super light 15" wheel I would recommend it. I will be going to another autox in april where I will finally be able to test out my many handling mods (in my signature) I've done since the last time I autox'd. It will be on the faster course where I think my mods will have more of an effect. I hope to be playing with the STI's this time!