I usually just spray WD-40 on my boots and other things made out of rubber or plastic-like AND I've had the same problem with my windows being sluggish too. I've sprayed WD-40 and it instantly fixed it, but then goes back to the normal slugglish strain. I talked to a friend that used to work at Mitsu, he said we shouldnt do that, instead, take off the inside panel to expose some cables that controls the windoes motion. He said these tend to get dirty and slow the cables down. I wasnt really sure that was the problem, cause every time i sprays the tracks on the window, it moved like it was new. I dont know. I'll have to try this out one day when i have time to take things apart. Just wanted to put my 2 cents in, thought someone could use this info and test it out.

I'll have to look into this heavy duty silicon soon and try it out. Thanks.

later,
Angelo