Black Again works great. GR40 works better.

but I would make sure to have all waxes/polishes removed from the rubber trim first with either a paint prep solution (pepsol or acrysol), 50/50 water/vinegar mix, alcohol/water, etc... once the rubber trim is clean, then use the rubber protectant/shine stuff.

word out from the motorcycle clan is a product called "pig spit" or something like that.. silicon base, won't dry out nor smear chrome/paint, won't collect dust either. i have yet to try it tho.