Damage? 0-60? Pshhhhhhhttttt, RELAX!!! Its nothing too complicated really... just stay on top of your regularly scheduled maintenance intervals, and it will all be fine.

This isn't FATF, the floorboards don't fall out if the Intake temperature gets to high, and in competition double clutching wastes time and mental focus. If you're really worried about your synchros, change your tranny oil to something like Redline, Pennzoil Synchromesh (Avail at autozone...) or Royal Purple MTF, and go back to driving it like you stole it...