Double clutching and heel-toe?

[aaronng]

my thoughts exactly. Why cant you rev whist in gear!

how else could u launch?

You can rev in gear. If the clutch is pressed in, you can rev as much as you want. The only wear in the gearbox would be the thrust bearing (which wears quickly if you like to clutch in and rev often). Double clutching is to allow getting into gear with non-synchro boxes, and can help prolong the synchros a little bit in a synchro-equipped gearbox. Heel toe on the other hand focuses on clutch wear only when releasing clutch after downshifting.