Well, I am not that bothered about going back to RE at the moment, as it was only done recently, so I dont feel its worth it.
But, I suggested Cooper & West before, becuase they give you graphs for both power & torque, for both @ wheels and a calcultated @ fly, plus lots of other additional data, from the trick Bosch RR system they have. Its only the @ wheels figures we want though.
When I was there last, we did a group RR session (again) and the readings people got there all seemed to tie in with readings that wed got from other rolling roads, so people were happy that the figures were pretty accurate.
Its also the place that Pipercross use to test the power gains from there air filters and is a very good system, so I reckon this would be the ideal place to compare the figures we all got at RE as its local.
Ok, so you cant accurately compare from one RR to another, but it will give a very good idea of how close the RE figures are...