There is at least one other US based offering for M57 tuning and it happens to be me and my company. After more than 6 months development on a multiple X5 I am almost ready to release the tune for the public. However there are few things that still hold me back. I would never offer a tune without a dyno charts and comparisons back-to-back with stock. In a 21st century claims for 10,20, 30% increase just do not cut it. It is a bit complicated and expensive to book a full day at a 4wd dyno (multiple tunes from stock to stage 4 has to be tested and documented)
Other thing that is important to me is that regardless I am active member here and try to help many members with their problems, I dont feel Ok to advertise without contributing financially to this great forum.
But just as a teaser, our Stage 1, which is completely stock engine, is projected at 320hp and 480tq. Stage 2, which needs only EGR OFF, should be over 350hp and 400tq and stage 3, EGR and DPF OFF, is virtually limitless. My partner Raymond (TRF performance from Norway) has an E46 race car with M57, which on a single turbo makes 450hp and over 550tq.