1) I have a 2010 ZR with 22k miles so mileage sounds good, but I'm shopping tires right now as I'm down to the wear bars. You may be looking at $800-$1000 in tires soon.
2) Most people's tops have been fine, only a few problems but it is a big problem if you are one of the unlucky ones. Paint does seem to chip easily from road debris, not worth passing on the car though, just get some matching touch up paint.
3) I don't have measurements but the seat does have height adjustment and will lean back some. Can't really offer any more advice, I'm 5'5"
4) I use mine as a daily driver as well. The trunk it wide enough but a bit shallow. If your car does not have a spare (most don't) there is a large styrofoam spacer where the spare would be. I removed this and replaced it with 2" of styrofoam insulation from Home Depot to flatten the bottom of the trunk. This gave me about 6" more depth and really makes the trunk more useful.
5) All 2010 models have the new stereo HU even if they were built in '09.
6) I curbed one of my rims about 2 months after getting the car. I had a local company come out and fix the rim at my home. 30 minutes and $75 later and you can't tell. I mean really can't tell, even up close.