Guys even the ATW figure can not be taken as gospel (far from it in many cases). If you look at how a RR works and the physical constraints and forces involved you will realise no RR can be correct. RR's are very good for diagnostics, mapping and comparisons.

People also used to swear by Engine Dyno's, which have the same issues with Real Life comparisons as RR do (if for different reasons), but again without doubt have their uses.

As already stated...... to find out how powerful your car is, get some timings down the strip or track..... thats the reality!

As regards to Cossie transmission loss..... it has always been quite high. Have you seen the size of the diff's on Cossies compared to other cars for starters!