Sounds strange!
I think everyone else has agreed that it is the engine mangement program that is a little bit different!??
BTW: What exactly is "The back box"??? (I´m just a stupid Dane with little knowledege of english car expressions...
)
I have driven a FR, and after the update of my engine, I would say it is impossible to tell a difference between the engines!
It´seems, amongst other small tnings, that the turbo now boosts a bit more... and since I now can here the "standard BOV" when I lift, I think it could be because of added preasure!?