The feedback on Bluefin seems to be indifferent and people have been pretty underwhelmed by the gains on the S3.
I had planned to go for Bluefin but after a bit of research decided against and went back to REVO for those reasons.
Staz has Bluefin but iirc and was only happy with his after some custom mapping.
Superchips do a 7 return on the Bluefin product so you can always send it back if you are not happy.
There is a 50-100 mile post map period where your ECU will adapt and the gains will seem to increase slightly, however from my experience there should be a significant difference imediately after the software has been installed so make sure you can feel that `before and after` difference.
My advice would be to have a run out to you nearest REVO guy and hand your money over. I did a 100mile round trip to have mine done and its a minor inconvenience for the end product, remeber too that the trip back will be a lot more fun and a lot quicker!
Good luck
Paul