only time I had issues with the JB3 was when it was first released (as I was the test dummy for the X series), but after the last update back in march '11 no issues with the tune... I've had another issue, but i don't think its the tunes fault... When I got the FMIC upgraded, the JB3 actually caused a boost leak when set to +5 over boost (because the silicon hose popped off the passenger side of the FMIC)... I need to update my sig block because I'm set to only +3 over with no pop off issues...
I may invest in a CP as well, but I don't see any that are compatible with the E70/F10 series... (X5 and 5 series share the same parts)
BMW X5 35i: Boopie Exhaust & Intercooler, K&N Drop in Filter, JB3 (3+ psi)
2013 Dodge Challenger R/T: CAI, Catch Can, Custom Exhaust, Headers, 87MM Throttle Body, Diablo Custom 93 OCT Tune