Hope you don't mind me jumping on your thread!
Well, after two months (letting the car run in) I finally got around to fitting my DTUK box this week. It definitely improves upon the standard GTD, no doubt about that! It is especially noticeable when overtaking.
Anyhow, I was curious to see if the power claims DTUK make were true, so I booked some time on the rolling road. As some of you were interested I thought I would post my results.
My car: Golf mk7 GTD, manual, 2015 build week 4 car, 1751 miles on the clock.
VW claimed: Power = 181 hp, Torque = 380 Nm
Actual: Power = 208 hp, Torque = 422 Nm
DTUK box (1+1): Power = 230 hp, Torque = 497 Nm
DTUK box (3+1): Power = 219 hp, Torque = 497 Nm
I would have liked to try more settings but I only had 40 minutes due to arriving late - maybe another session in the future.
Overall I am pleased, especially with what the car was pumping out as standard! The DTUK box, whilst not quite matching the 239 hp claimed, gives a nice boost. The torque is where it's at and the peak comes in 500 rpm lower than the standard car @ 3500 rpm.
I used Motorscope at Northallerton. This is the same place DTUK used for their GTD dyno run, albeit they had a DSG model. The tech said DSG cars (automatics in general) usually produce a tiny bit more power on the dyno due to how the measurement is performed, which could explain some of the power difference from DTUK claim.