My 1150 (2k single spark) has both 17" Alloys and original spoked wheels. I've got BT020/021 combination on the alloys and Distanzas on the spoked. I put the spokes back on just before Xmas and the difference is very noticeable. The handling is FAR superior with the alloys (not that there is anything at all wrong with the 'normal' handling), it steers quicker in a very positive way, you only have to 'think' about dropping into a bend and it's there, but never in an alarming way. I've had no stability issues at motorway speeds, solo or two-up, but I haven't tried it fully loaded yet. Personally I think the bike looks great whichever wheels are on it, the only slightly odd looking things are the spacers under the fork brace which drop the Carbon Fibre front mudguard down closer to the wheel, although they're not too noticeable at first glance. Still uses the standard exhaust on the 1150. I haven't checked the speedo against my GPS to see if it makes any/much difference to the calibration, if anything it should read fast with the smaller front wheel on.
All in all a very worthwhile conversion IMHO