I run one of these. Well made, certainly the finish is miles better than the gsr box I had in the m3 before. Alpha-n mapping was done for £350 by regal automotive after recommendation. I doubt they'd repeat the price as it was a you suggest a 'mare for them. I did tell them the ecu was very different to the e46m3 and to be fair they did a great job, even if it did take 4 days and honoured their original quote. I did give them £50 for dyno run electricity. I have print outs from about 20 runs. The map I have now from them behaves far better than the evolve map I had on the m3 for gsr box, it's totally flawless, throttle response is far improved, and post 2k revs the power curve is almost linear to the red line, in fact mine increases post 6.5 but I have some fancy cams.
Give them a call. Alternative is roy's custom map guy, which is expensive at around £1k, but i hear good things about him. Evolve map on Z4M carbon Airbox is not fantastic as far as I am aware. No personal experience though.
