reving a cold engine wud damage some engine parts, lalo na if ur using mineral oil (which goes down sa sump). sa synthetic medyo ok pa (due to synthetic oils leaving a thin film of oil sa loob), pero not really advisable. atleast 5 mins mo muna syang i-idle before u go, para atleast mag circulate na yung oil sa engine mo.

yung revving before shutting down, di naman talaga kailangan (in fact di nga advisable), pero kung maganda yung tunog ng makina mo... as in ... vroooooommmm ppssssshhtttt... nakaka tempt gawin :D