With revo you can adjust fuelling timing and boost levels to suit your car. Every car has different settings to optimise the potential of the remap. I.e some cars can run different timing and boost levels with the engine being happy with where you set them, others aren't. If you go to alan, he'll set your car at base levels and send you on your way, maybe check your car with vcds to check for fault codes.
Other revo dealers will check with vcds, do a rolling road before remap, test different settings on the rolling road, when settings are found where the readings are healthy, another rolling road will be done to see what power your car now makes. Then a test drive and data logging to see how the readings are on the road.
I know what I would prefer....
Rolling road graphs also help to show whether there are and dips etc which can also highlight other problems that you car may possibly have that won't always show up with a vcds scan.
