Just this week I replaced my ESS tune with a BPM Stage I tune and my experience is pretty much identical to yours! (including the months of prevarication and 'conversations' with the GF about spending more $ on a second tune! )
It's only been a couple of days, but the difference in drivability is very pronounced. I definitely have that big grin on my face again.
In particular, with the ESS tune I used to have a rough cold start and idle, fairly frequent hesitations pulling away from a standstill, or when trying to accelerate too suddenly in the lower half of the rev range (as happens frequently on the freeway) or on a hill.
So far, it seems like the BPM tune has none of these issues. I can pull away from a standstill with much more confidence that the car isn't going to hesitate. I don't know if Mike changed the throttle mapping, but the power comes on more immediately and there isn't a 'dip' when you hit about 2K rpm.
Power delivery is extremely smooth and the car almost feels lighter. Just a small squeeze of throttle produces an immediate and progressive response, even in the bottom half of the rev range. The net result is that it *feels* faster around town and on the freeway - and that's what makes all the difference to me. These cars are always great fun if you keep the revs above 6K, but that's now how you drive on public roads.
I couldn't say if there's much difference in top-end power between the ESS and BPM, but given I use this car for my daily commute, the BPM tune is a *much* more enjoyable drive.
I'm going to wait a week or two to make sure, but so far I'm *very* happy.
...oh, and it doesn't really need repeating, but Mike's customer service is as good as they all say.
