When I first got my 02 B6 I added 3/4" additional preload (via ABS pipe) and raised the oil level by adding 20cc more fork oil (20W) to each leg. This raised the bike a little at rest and prevented bottoming under hard braking. (The additional oil level causing the air space to increase the spring rate at the end of the stroke).
I was OK with this for the past two years, but the bike still uses up the middle of its travel too quickly. But this is the cheapest thing to do.
I have just ordered Progressive Suspension variable rate springs, as based on most the conversation here, it is a noticable difference. Also, after 3 years the stock springs are not getting any better, just slowly sacking out some more.