Buy one, it’ll be ace*
* and expensive to run, a friend has an M6 (same engine), he gets 13mpg driving to and from work.
SMG gearbox is supposed to be a potential trouble spot, so make sure you get some form of warranty.
Engines are reliable.
I recently owned an e92 m3 (sold it last month and swapped to an m135i), the M3 was/is a great car, but again fairly pricey to run, 19mpg average over 25000 miles, tyres are £1k for a full set, and will last 15k miles if you dont wheelsping off from every junction. brakes £1500 for a full set, should last 60000miles (excluding track days).
If you want one, get one, scratch the itch for a couple of years and move on.