PSA: VSA / ABS troubles? clean your sensors.
 

Just a PSA for anyone else who runs into this problem:

I was having increasingly early VSA activation during street driving, to the point that it was going nuts even in very mild turns. Total killjoy even when putting around town and it was driving me crazy. Seemed to get worse and worse the more I drove it. I found a thread about ABS kicking in too early on the track and it suggested cleaning the ABS sensors. VSA utilizes the same sensors, so I pulled out all the sensors and cleaned them thoroughly with brake cleaner, as well as their mounting points. VSA problem solved!

You'll need:

- floorjack
- brake cleaner
- paper towel or microfiber towel
- light grain sandpaper if your mounting points are too caked up to clean (mine were okay)
- 10 mm wrench to remove sensors

Takes a couple minutes per wheel and well worth the effort. Now the car can develop a little slip angle before VSA engages, just like it used to. It's so easy, I would recommend cleaning them every time you work on the brakes.