With the 58's I was getting 4-stroking anytime I was cruising at a steady speed, not just wide open. If I accelerated, it would smooth out immediately; this would be like going uphill at WOT. I've noticed occasional 4-stroking with the 56's, but nothing like it was before.
Gabe, both of my bikes came with a rack like Karl's. I've got one on now, on the same bike as the windshield and saddlebags, sort of a 'ped "dresser". I think I may leave the other bike free of accessories. If I decide I'm not going to use the rack, you're first in line for it.