Got the spitfire and tested it on the trails today. I had a ***** of a time trying to figure out where to mount it along with my hand guards, gps mount, etc etc... I eventually got something figured out, but the space is too tight for the little spindle things -- so I just used hex head bolts of the same thread and used locktite as you suggested. I will have to check and make sure they haven't rattled loose though.
As you said, it works wonders on the highway, but yeah, I hit it a few times on the trail although I got better as the day went on avoiding it. Unfortunately I'm going to have to put up with it as I live too far from any trails.
This DRZ is awesome though... I rode it today in Beaver Valley. Down a very rocky path on the one side, up an abandoned ski kill, then up a very rocky East side and a sidetrack through the forest due to a fallen tree. This bike handles everything with ease and has more than enough power to just throttle through nasty stuff. There were some uphill rocky bits that if I tried to go slowly I would just be spinning rocks back down the hill... so I gave 'er **** in first and powered through it.