I have the JB3 in my X5. Honestly, not that big of a difference, I have to strain to notice a change in daily driving. Timing with a vbox I had an average of 6.1 sec 0-60 and with the JB3 it averaged 5.9 (didn't run the 1/4). I had a Procede on my 335xi and that was a massive difference (about 0.7 sec faster in 0-60 and about 1 sec faster in the 1/4 mile).

I hope the n55 tunes catch up to where the n54 are now...Would love to see a higher stage JB, Procede, or Cobb solution in the near future!