Hey, first post ever, thought I'd give my 2 cents.
I drive a 2005 M3 SMG and I've been having this same shuddering problem. But mine has ~72000 and it shudders when it's both hot and cold. I took it to my mechanic (we are very good friends) and he said it needs a new clutch, but I can wait a little longer before changing it. He said it will cost about $1500. Not the greatest news, but I trust him. This could possibly be the same issue for you.