Gareth,
You can go beyond the end of the MAP sensor, providing you know how to EXTRAPOLATE. Probably wise if YOU don't, as you didn't even know the meaning of the word... .
thats bollox mike, all you do is write your fuel for your highest boost on the top line of your map, the driver is the only person who can stop damage by keeping an eye on the boost gauge!
i wont be going past the end of my map as i have a five bar and a t34