I agree about quoted figures. You just have to read up on the different maps and choose what suits you.
RICA and BSR couldn't/refused to answer simple questions when I queried the quality of the maps, MTE were spot on and didn't have a pushy sales manner, just gave me the answers to what I asked
With the custom maps, that's what MTE were doing at Bruntinghthorpe, just see the T5D5 forum for details - there's some SERIOUS performance Volvo's over there! As with Badgerbox's detailed experience with custom maps, RICA (previously) and then MTE, the quality and service of MTE is in a class of its own.
You need to spend some time on T5D5 perhaps just reading up/asking about the custom mapping.