I got a 2011 335d a couple months ago, and put a JBD on it after about 4,000 miles. I maxed out the setting and and the car drives like a monster and fortunately I haven't experienced any error codes.
I hope you get it working. The 335d isn't bad as-is, but it's hard to describe the white-knuckle fun/terror you get at 2,000 rpm to your friends with an "i" instead of a "d" on the badges of their cars. They need to feel it so they can be jealous.
I just wish the suspension was firmer. I hit the bumpstops on speed bumps that my M3 would laugh at.