As requested, some feedback after a couple weeks of driving with the Bluefin on my X5: the power gains are definately noticable. There's a hill in Devon that I go up regularly and the X5 just munches it like it isn't there, I really was extremely impressed with the performance on this hill! Throttle response also seems to be improved, most noticably at lower speeds. I'm sure fuel economy has improved too. On a run I get over 30mpg, driving no differently to how I usually would (i.e. not strictly abiding by every speed limit

) . Unfortunately I'd only taken the car on 1 decent run prior to installing the Bluefin (I've only had the car just over 3 weeks) and as it was so new to me I didn't really worry about the MPG on that occassion I'd have been surprised if I managed to get 30mpg out of it. Anyway, sorry it's not very technical but to summarise - I'd recommend it, power delivery is more intense and driving is therefore more fun!