[b2tf]

Thought I might update this thread, I drove the car in question the other day and there is definitely a noticable change in performance following tuning. The owner ended up using Sniper to tune the car and the current tune in it is the 'performance' tune as supplied by BPR.
I think based on this experience and also how far my jaw dropped when I saw the amount of reading to understand/use Quarterhorse, I would also choose Sniper if it were my car. It is essentially the same as Xcal3 with a few changes in regards to who/how the tunes are uploaded.

I think the owner of the car considers it money well spent and after having a drive of it I would tend to agree.