Surprised at what mine produce with what the minimal bits done to it.
I think to be quite honest the only real reason to have a custom ecu remap isn't to gain power really. We all know the engine is not very tuneable, and gains are always small. But to make them run smooth, react better, have a better feel to drive, and to increase the torque throughout the range.
my car, had a horrible flat spot, after exhaust change; now the flat spot is completely gone, initial torque from down low is far better, this making the car much nicer to drive and pulls better through the mid range.. Which at the end of the day is what it is all about.
I went to AmD and was very happy, a very close friend has been involved with them for years, (drives in touring cars and GT's) and recommend them to me, of which I can't fault.
We all have different opinions on different places and no one will every agree!
But as long as your happy with your car and it drives how you want it to, I know personally I'm not bothered if perhaps the rollers I used are slightly. High, or if read slightly low. Unless you go round to a large number of rolling roads and take an average you will never truely know ...
Regardless of where you get it done, hope when it is done it's running sweet!