That shouldn't really be a concern Sam... The 5M starts running out of breath around 5800 rpm's anyway, so its a waste to go that high... When I am running hard, I usually start to shift out around 5500 or so...
my redline is supposedly 6500 - Ive taken it to 7g a few times with no trouble, but like Bob says, not much point in pushing it that high. With a bit of an intake upgrade, Ive found shifting at about 5700 makes for best acceleration.
Yes, but it is not always about optimum power. Alot of the time, it is good to know how high you can go just for shift-convenience alone.
At the autox coming into a corner fast in first, near 5500rpm, if you shift right then while pushing your lateral traction to the limit, you will most likely induce oversteer, bleed speed, and slow down. Now, you have another 1200rpm that you can use to get your exit speed another 6-8mph faster, given it wont be as fast as when your in the powerband, you just flat out CANOT shift at this point, thus you use those extra rpms.
I did an autox once, found out in the first heat that it can be better to hold it up against the redline rather than shift at the end of a straightaway. No sense bouncing up against fuel cut-off, but lifting off just enough to stay at the top of the powerband until you have to brake (please excuse my lame old man novice comments)