I've gotten so much useful information from this board since I took delivery of my new '99 M3 in July that I've been anxious to contribute something. Here a tip that might be useful.
I know lots of you hate those ugly sunvisor stickers on late-model M3's, and most of the info out there suggests various solvents to remove them. Most commonly, Goof Off is used, but this is a xylene mixture that also softens vinyl (it's nasty and carcinogenic as well). Here's a simple method that works great. Remove the sunvisors and place them on a flat surface. Using a 1500 watt hair dryer, direct hot air onto one of the shorter edges of the sticker. Holding the drier 3-4 inches away provides enough heat to soften the sticker, but it doesn't effect the vinyl (a heat gun is way too hot for this). Using a thin-edged plastic spatula, gently peel the softened edge of the sticker back. Keep doing this progressively, heating and peeling, until the entire sticker is rolled up on itself; at the end it can be lifted off the visor in a single piece. It takes about 20 minutes to do each visor. At this point there should be no remnant of the sticker on the visor, but there will be a thin residue of shiny adhesive where the sticker used to be. This can be removed by soaking a paper towel with laquer thinner and rubbing it gently over the entire surface (as suggested by Jim Bassett), then drying it with another paper towel. Repeat this 4-5 times and all the residue will be removed. Let the visor dry overnight, treat it with some vinyl dressing, and the job is complete. I recently used this method to take the stickers off my black visors, and they are PERFECT; there is no way you can tell that the stickers were ever there. Good luck!
('99M3/2, silver/black, sharked, Euro ellipsoids, clear lenses, 35% tint all around, "M3" vanity plate).