Thank you,
I had been looking at Evolve; only because it has been a popular move on here and people have been running it for quite a while now.
However, I would assume that Quantum, Celtic and any others all have the same basic premise, so the same logic should apply.
Nope celtic are a premium provider, they write all there own maps and have development cars on site, including a rather beautiful little alfa, a golf hillclimber and a porsche (917 I think).
They do not buy maps from other providers like many do, if you take it to them you get a pre and post map dyno reading so you know for a FACT what your paying for. They also give you a 12 month warranty against any related failures!
I have had 3 cars done by them C63 - Z4 23i - Z4 35i last week.
Picture is my 35i (Scarlet) on the dyno last week.