No chance 40bhp mate, 10bhp is more like it. Mine has an Alfatune map on it and equal length front pipes and its not as quick as a standard GTA, but it does feel a bit healthier than most GTVs I get to drive, especially low down in the rev range.
I got 83 lb/ft and 60bhp from remapping my old car, when I saw the figures for v6's after remap I was bitterly disappointed. I guess that's what you get with N/A engines. Not worth the money IMO for 10bhp.
To be fair, even with £275 rolling road is a very reasonable price> It would be interesting to see before and after RR graph. Depends how much they can "tweak" the RR to "improve" the result. Might be worth a punt as they are only down the road.