I sent Mike Benvo a link to this thread and just spoke with him and he brought up some pretty good points about why results on all the cars dynoed were not expected. First off I had concerns with air flow from the beginning and that's probably a pretty big reason we're low reading. They had one wussy fan when I've seen M3s dynoed with 4 MONSTER fans. There was not good air flow. Also, the placement on rollers and strapping was a little wishy washy and he thought that could make differences too. And then there's other stuff like wheel/tire diameters, etc. But overall, it's too hard to see an improvement from a tune unless you get a baseline, tune it while still on the rollers, and then run it again. All I know is the car does not at all feel like it did before the tune and I'm happy with it's performance. I just wish I hadn't even bothered doing a dyno run but hey, I had a great time hanging out with everyone. Next little meet up we'll do a drive instead.