i done 25 miles too. last 7miles were the slightly downhill gradient of M62 into Brighouse, pretty much just tickled the throttle enough to get into the Shell station off of J25. wouldn't want to do it on a regular basis.
when coolant is filled at the factory there seems to be a small airlock in the system, over the first few weeks it self bleeds, hence the coolant level drop. quite a few 7R owners have found that after topping up once, it won't drop again. just monitor it.
Akrapovic sell a full system and tail pipes in carbon fibre for mk7 GTi on demontweeks for £3663, think it includes carbon fibre defuser. so I reckon that'll give a ballpark figure
I was actually referring to the dtuk, not APR, i wasn't really clear. at the time I was attempting to multi-task and I merely proved that I could do two things at once, both badly.