Mapping your car would void
some of the warranty. For example if the engine goes bang, they would blame the remap. If a shock absorber fails, they can't really blame a remap for that failure
PDT get great reviews on here (and they provide lots of support) so you can't go wrong there
I used to specifically ask them not to update the ECU map to avoid this worry. Sometimes they can't update the map if it's remapped anyway.
Greenlight are a fantastic insurer. Having a remap and switching to Greenlight was actually cheaper then having a stock car with a main stream insurer