that wont work, you need to rev match in dog boxes to ENGAGE the gear.
Rekin, from what i got, you were asking why people let the clutch out as opposed to the way your doing it, everyone else is telling you why people double clutch, not why they do it that way, so:
you let the clutch out while its in neutral, and give it a rev to match the speed of the clutch with that of the output shaft on the box, allowing for the raio of the gear your trying to grab. a practical example,
say you've only got two gears, 1st and second, the ratios are 1:1 (2nd gear) and 2:1 (1st gear)
your doing 20km/h in second at 1000rpm, you double clutch, bring the revs up to 2000rpm, so your clutch is spinning at 2000rpm, your output shaft will already be spinning at 2000rpm, and so will first gear, everything is the same speed, gear will slot straight in.
if i f*cked any of that up please correct me so i dont confuse rekin
PS - thats how u shift without the clutch also, pull it out of gear, rev match, and because everything is pinning at the same speed, gear with slot straight in, but its hard to do, i still crunch occasionally when i do it, and i practiced it a fair bit. man i do some terrible things to my gearbox.....
PPS R33cruiser, none of what you said makes sense, its got nothing to do with running at the strip (you said e.t. and im guessin your not talking bout the litte green dude on a bike lol)