I played around with the BMS PBX and to be honest, I didn't like it. Maps 1 - 3 give you varying throttle maps for sharper response as well as a slight tune. I found Map 3 was way too aggressive and artificial feeling for my liking, Map 2 was better. Map 1 was also not too bad. Couldn't really feel that much of a difference between Maps 1 - 3 and 4 - 6. But with Maps 2 and 3 for instance, while town driving speeds, gear changes did feel a bit more positive, I found that flat out accelerating through the gears was very jerky and tricky to get right compared to Map 0 (PBX disabled).
The problem is that all the PBX is doing as I understand it, is changing the throttle response curve and I gather with the tune it is also making the 100% throttle value earlier in the throttle travel, so pressing the throttle pedal further and to the floor makes not difference. But the biggest problem is that the PBX cannot overcome the default throttle delay - this is what is causing the problem. By sharpening up the throttle sensitivity but not changing the reaction time, all that you end up with is a more annoying and unpredictable throttle.
So I gather the AA tune which flashes the ECU is able to overcome this. I have since removed the PBX and just living with the normal throttle feel...
BMW E90 330i (M) '05 (His) | (Hers) BMW E46 320i f/l (M) '03