I haven't driven the Z, but a few comments

1) the first to second shift on many sport cars takes abuse, so designers beef up the syncros a bit.

2) syncromesh between gears actually slows the gear change compared to a crashbos shifted well.

3) Ferrari's are notorious for a hard first to second shift when cold, that is why many owners shift from first to third on a cold box.

4) not only will an engine warm up, but a rear diff will also warm up and many people think warming all the oil's on a car helps reliability.

5) drive a Honda S2000, I have read that is the nicest gearbox around.