I know in an ideal world we would get custom tuned on a rolling road and set up but I can see why the places that charge a couple of hundred quid compared to 500 get there custom, Theres a few places near me offering VW Golf 5 2.0 TFSI GTI 200 200 hp up to 242 hp /280 NM up to 352 NM , they pretty much all claim the same figures so I guess they use the same maps etc ?
Are they bad to use compared to a place that would say put that map on and then fine tune it for each individual car