The rules?
#16
SC8 wheels are compatible with normal SC tires I thought. Most local clubs shouldn't give you too much grief if you are running sc tires. A 17mm conversion isn't an advantage if you are running SC8 wheels or the aforementioned 17mm wheels from DE racing.
#17
Tech Regular
Ahh, I thought they were bigger. If it's just the hex, nobody will notice. I've seen people running 1/8th buggy wheels on 1/10th SC, so I thought (clearly wrong) that the SC8 tires would be similar to truggy tires in diameter...
#19
The level of talent in Australia is a bit lower than alot of the other places in the world. For example the highest placing Australian at the 2011 IFMAR Electric Worlds was 66th in 2wd and 59th in 4wd. In fact the top Australian only beat 1 driver from the U.S. The U.S. driver was Zach Rogers in 4wd. I have raced with Zach and have been on his pace, and I have got a lot faster since the last time I raced him too. Now maybe he has got faster too, but still Australians just are not that fast on a global scale. The faster you are, the more in touch you are with your car. A new guy is not going to notice inconsistencies in their car due to sidewall flex, vs the inconsistency in their driving whether they are in the U.S. or Australia, but in the U.S. we have a lot more people that would be able to tell. Go ahead and glue up the same tread and compound tires, with the same inserts on SC8 wheels, and regular 2.2/30 SCT wheels, and see how many people can tell the performance difference.