the only good use for the manual mode is that if you floor the throttle when overtaking and DONT use the paddle shifters to change up ,you can get the engine to redline ,at which point the gearbox will automatically upshift,since maximum power comes in at fairly high revs it makes for quicker acceleration,you really cant damage the engine as the rev limiter kicks in to prevent you doing so but I use this feature regularly and you really shouldnt worry about the revs ,Hondas thrive on it ,cars or motorcycles