a company i used to work for over here had a dynapack 2500 chassis dyno. these are the way forward for mapping cars imo . it can hold any engine at any given rpm with all the power you can throw at it and theres is never a chance of wheelspin because its bolted to the hubs of the car. it could in theory stop a 1500 bhp engine dead in its tracks (not that you might want to!) it also imo lets the car move about under load as it would on the road as there is no strapping involved. its awesome to see a big bhp car squat as it comes on boost