I took my car down to Cituning and had a power run done for £35.
Here are the results .. 93BHP at around 6,500 revs, and 116Nm of torque at about 4,600 revs.
This works out to around 130BHP/ton, giving standing quarter mile speed of around 95mph.

The rolling road at Cituning is a Dynomet, check out their homepage here.
OTHER ROLLING ROAD LINKS:
Exellent page on why you shouldn't believe the numbers !
Subaru Imprezza Turbo ... Excellent Site, loads of data !
Very good description of the G-Tech Pro Accelerometer !