+1 the JB4 is about as specialist as you can get for the N54.
I too was a doubter initially, but not now, no way would I go for an 'old fashioned' fixed, inflexible, expensive remap.
People like BW chiptune (who?) are usually jack of all trades who just load up maps they've bought form someone else, very few if any of these 'mappers' actually understand / crack the systems they are working on, they just buy-and-load.
And no one will know the N54 like BMS / N54tech do. How can they when they are chipping everything from a mini to a transit van, they probably see an N54 every month or so and don't have time to study it.
The JB4 is pure N54 by design (spend some time reading on N54tech.com, an entire site devoted to the N54)
Fixed maps give you one go and you're stuck with it, the JB4 has so many benefits, from the switching and adjustment to suit your car, the autolearning features and logging and free regular firmware updates etc.
The performance is probably similar as its the same engine in the end, but the way the JB4 development keeps on going, you just download the lastest version every month or so (for free) and get new features / improved performance.
Can't beat it IMO.
E63 AMG here at last!
Last edited by doughboy; 09-19-2012 at 06:07 AM.