I daily drive my 98 M3 and while I agree that it certainly lacks a lot of the modern luxuries and accoutrements that my 2004 TL had (bluetooth, heated and uncracked leather, etc), I kind of like the simplicity of it. EVERYTHING in the TL was computerized and at the time it got totaled it was starting to have a lot of little electrical gremlins and that car was only seven years old. On top of that, when I got the TL I immediately got to modding it changing out the suspension, wheels, adding the ASPEC kit and doing various other mods to get it to the point where I was happy with it. With the M3 I simply don't really feel the need to mod it right now. The car looks great as it sits and it is an absolute BLAST to drive.
All of that being said, I don't regret my decision to buy this car at all. I've had people say that I "downgraded" by getting this car after the TL, but I don't see it like that at all. When I was a kid I had one of those BFG posters on my wall with an e36 M3 and I wanted one SO bad. Now I have one and granted, it's a much older car now, but how many people can say they own one of their childhood dream cars?