I would sell it. This has come up before with outher CEG'ers and I've told them to keep. But in this case, sell.
WHY?
It sounds like you're tired of the car and need a new one. The '00 CSVT is the best production year (I have an E0), and had "the least problems." If you can get a buyer, I'd get rid of it, because the maintenance you have outlined will set you back $2k, and that won't add to the value of the car.
As for a "new car" I wouldn't look into used M3's or the such. You'll be dropping A LOT more in maintenance in those cars, and parts are far more expensive, etc. For 13.5k you could get a pre-certified used 325i or something and not worry about expensive maintenance costs, etc.
imo.
