hi , im looking at getting a xr6 turbo and my friend has the ba model and they said there were a few problems with it and they fixed it with the ba mark 2, I just want to know is there much of a difference in reliablilty between the ba and bf, because the ba is alot cheaper, and also perfomance wise the bf has 245 kilowatt, is it much quicker then the ba, is it worth spending more for the bf? also is the 6 speed quicker and more fuel efficient then the 5 speed?