Best, as in number of features and function it would be the Blitz SBC i-Color or HKS EVC, both are able to map multiple boost settings against rpm, speed, throttle position, etc.

which helps to maximise boost and turbo response at all speeds and in all gears.

However to get the best out of them takes a LOT of time setting up.

I've used both and preferred the HKS EVC because it had the clearer screen and was able to be linked with the HKS F-Con ECU which I was using at the time.

HKS have just launched a new version of the EVC
http://www.hks-power.co.jp/en/products/ ... /6evc.html