[gasnet]

jb4 on older cars is fine. On newer cars its just not great. ECU is just to smart on B58. I have a Z4 M40i and the best way to tune it is MHD. Only problem my ECU has to be benched in order to work. Also a lease so thats out. I have jb plus on mine. Seems to make a little difference but who knows. My older Z4 with N54 was very noticeable with jb4. The biggest gains i ever had was another Z4 with the N20 on a Dinan tune. Wow!! Like a different car. The best route for us modern B58 owners is to bench ECU/DME and use MHD or something else that tunes the entire engine. I say bench because unless your on original software its just not possible. After much back and forth with MHD this is the only way for us USA B58 owners with Z4 or M340i. There website only refers to Euro tunes on Z4 and M340i. After much arguing with MHD they finally put an asterisk next to Z4 M40i and M340i. The asterisk means benching your DME.