I'm also on the fence.
Why tint: Recently I've been having a lot of people pull up along side and try to race. Would be nice to just be incognito inside.
Why not tint: I've got a pretty unique combo in Sparkling Graphite on Bamboo Beige. The colors just pop when you see the car. Tinting the windows would definitely take a way from that.
2008 E92 M3: Sparkling Graphite | Bamboo Beige | 6MT | CF Roof | HRE | Catless Eisenmann Race | BPM Sport | Swift | Arkym | Mode Carbon | M.Perf