I had upgraded my e90 328i with a 3 stage intake from a 330i, and needed the computer retuned and after some research and some advice from BMW-E90-HQ, I picked BPC. While not wanting to take a day off of work to drive 400 miles round trip, I picked the DIY option and ordered the DIMSPORT programming device from them, pretty straight forward and easy to use, even for a person born before we sent men to the moon. Download my DME software, send it to them, they modify it and send it back and you write over your DME software. I think I started my download around 10am, and had the updated software back from BPC around 2pm. It's not 335i power but I'm happy with the results