Keep your current ride and save/invest the money you're gonna spend on upgrading.
You have a short drive to work and don't spend much time driving on the weekends. It'll be a waste to upgrade to a performance car and having it sit in your garage.
Alternatively, for the price of a new M3 you can buy the new 5 series(if you like the styling), or buy/lease a 2003 CPO 545i. You'll have a fast, luxury daily driver without all the "perfomance" mods to worry about.
If you must trade up to another 3, then I would wait for the new 3..
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition