R100GS Progressive Suspension Fork Springs
No pictures on this one, just a quick "I tried 'em, and I didn't like 'em." I weigh 165 pounds, and I found that the stock springs provide the right amount of sag and resistance to bottoming for me. If you weigh more, a stiffer spring may work better for you. Only problem was the bike came with Works Performance springs, which I didn't like, either. So after souring on the Progressives, it was an easy trade to Gene, who still had his stockers. He's happy with the stiffer springs, and I'm happy with the lighter ones. He weighs about a third again as much as me, though.
A lot of guys complain about front end dive with the factory springs. There are two things you can do instead of to going to a heavier spring. The first is to try a heavier fork oil. The GS uses one leg for compression damping, the other for rebound. The brake caliper side houses the compression damping circuit, the other side does rebound damping. I put 15W in the compression side, 10W on the rebound. That's up from the factory recommended 5W and did make an improvement. Ultimately, I installed a Race Tech Gold Valve Cartridge Emulator and am using 15W in both legs. It's the best setup I've found so far.
With this set up, the front end is supple, with good small bump compliance. I've only managed to bottom it out once, and that was heading out of Saline Valley on a mud and sand road in the middle of a hell of a rain and wind storm. I was in kind of a hurry to get someplace warm and dry before the road washed out, and the extra speed helped get me through the usually dry arroyos. 'Cept the arroyos were now full of a foot of dark brown water that hid all manner of rocks and ruts. Going across one of these the fork bottomed out. It wasn't a harsh bang, and this isn't something I do all the time (in fact, I hope never to repeat that particular ride!). So I'm satisfied the fork is using all of its travel and the damping isn't so high that the ride is harsh.