Vf39 p18 on a stock ej20 seem to come on boost/spool up to early. Have read up about it. As I can't Stab the pedal n gun it like you should be able to, but if I take my foot of n gently ease throttle it boosts beautiful. Also my idle is about 1100 when warm. Have checked checked and cleaned known working tps and Iacv. Would I need to down grade turbo? Running a stock z4 ecu withs 440s and upgraded fuel pump.

Cheers Josh

I have got a few ecu chips I had made up for the RS you can try, one of them is a MMS chip, let me know if you want to try.

What's the go with the chip? What's on it ? What's it change on my z4 ecu which has a slight remap for injectors

They were just remapped for better performance, higher boost, more advanced timing, pretty good results compared to the factory Z4 computer.

I'm keen a chip they suit a Standard rs ecu or the z4 one