No complaints with the Avons, I've had it out to West TX on an ironbutt ride and was able to push the bike to it's limits, no vibrations at 105+ for extended periods (at 100+ degrees) and no traction issues while scraping a floorboard.

Ride & handling (for me) is as good if not a little better than stock, however my bike is stiffer (a good thing) due to the progressive monotube 2" front drop.

No ABS on my bike.

I went with the HD kit and purchased through Lakeshore. I really like the forks on Texassg's bike though! I would definitely lower 1" with a 21" wheel. I have no issues with ABS. I taped a 1/4" nut on the tire to check if it rubbed. Mine rubbed ever so slightly with my metzler tire so I drilled the rear fender holes out with a 3/8" bit and tilted the fender a little. The job isn't hard with the manual and info here. An extra set of hand helps when putting the fork caps back on. I added ricor intiminators and I really like the front end performance now. Lots of discussion on threads about the amount of oil to add back in. I would follow the procedure in the manual and measure the height of the oil instead of adding a specific number of ounces of oil. That's the most accurate method if you are modifying fork internals or not completely flushing fork components. You can use the tool to tune your forks on the bike later as well. Monotubes are a different animal, can't speak to those.

Maybe a silly question but when you are talking about lowering the front end 1" to accomodate a 21" wheel you going with shorter springs or raising the fork tubes in the clamps? My FLTRX has the dreaded head-shake that HD knows about but claims is normal...curious to see if a wheel/tire change cures the problem.