[evermire]

I transferred mine from my previous 340i to the new M340 about a month ago, no issues so far. I need to buy the BT kit as JB4 doesn't have dash compatibility with the digital cockpit, which is what I relied on for changing maps and deactivating. Also, I couldn't figure out how to enable (if it even works at all) the can flap open feature since that was only accessible from the stalk controls (no controlability from the PC application over USB).

As far as performance, it's been great so far but I don't regularly push it to max boost levels. It is definitely making a difference being set on Map2 in my case.

Last comment, install was pretty straight forward and comparable except for one aspect in my opinion. Getting through the firewall. There is a black plastic piece in the area of the drivers side hood hinge that needs to be removed. It takes some finagling but it can come out without damaging anything. Once that is removed, it's fairly easy to punch through the silver metallic sticker that covers the access into the drivers footwell. I used a fish tape and didn't even have to remove any lower plastic pieces in the footwell, as I was able to wiggle the fish tape to pop out around the OBDII connection, then feed the small end of the JB4 cable back through to the engine compartment. Everything tucked in nicely into the area under the plastic cover.