Well I just got my Dinan CAI put in and I am thinking about adding its counterpart, the stage 2 software. My thoughts are that it is a lot of money and doesn't sound like it adds much of anything for the cost. I believe it only rids you of your limiter, and changes gears 250 rpms later than a stock bimmer. Does it do anything else? Also if someone has it can they let me know if there were any noticible differences in their car, and if they thought that it was worth the buy!