Something to consider, when I owned my 335i vert a group of us from the Bimmerfest forum met during a day in June and traveled the roads in the White Mountains area (Kanc, Bear Notch, etc). The highlight was a drive up the Mt. Washington Auto Rd. It was not for racing but fun of driving the roads before the vacationers with their campers started clogging-up the roadways. There were some M3 owners in the group but mostly 335i/328i with a few Porsche 911/Caymans thrown in for variety.
If anybody is curious to see the history, go to the website under the E90/92/93 forum and search "Climb to the Clouds". It has been going on for 4-years with one planned next June (overnight stay at the Mt Washington hotel).