Kurt will build a Kinetic Road Machine with custom power curves relating to any weight you want. The stock unit is calibrated to 165 or 170 I think. Their literature says they compared actual output using a powertap on the road to set up the resistance curve.

It's really hard to compare road -vs - trainer for me. Everywhere I ride on the road is rolling to hills to mountains with wind and weather variables. Unless they build a velodrome near me it just isn't the same. That said, I really like using the trainer when it's raining or after work.