I dont understand how you can be questioning all this lack of power chris, when you still havent even had it on a RR to see if it has lack of power or not?
If you want your car datalogging I've offered to help in the past, only takes 10 mins of my time if you want to drive down the road and see how its performing. I live about 15mins from the tunnel.
I'm running a stage 1 map at the minute with stock everything else, a simple side by side run will see how it copes, and by my MAF figures, my car must only be running 270-290bhp, which is a fair comparison if your car is underpowered?