If you're in the market for a high performance scooter, you might take a look at the X-Scooter.
http://www.dive-xtras.com/scooter/indexcon.html
(here's a link to the entire website:
http://www.dive-xtras.com/index2.html)
It's depth rated past 500fsw, single battery model weighs ~32lbs w/battery (so you can take this scooter on trips abroad w/o getting hit w/extra weight fees from the airline), is just slightly positive in fresh water and easily weighted for neutral and balanced for excellent handling. It has 70+lbs thrust, speed in the 250+fpm range with a fully dressed out tech diver (twins, stages, etc.). I've owned Makos & Gavins (and driven SS's) and this scooter surpasses all of them in speed, handling, and maneuverability. It's also lighter than a Gavin, a Mako, and even the Torpedo. The X has a brushless motor and uses a Nimh battery and has three different size models that are all interchangeable. ~1 hr, 2hr, and 3 hr burntimes (at full power). Uses a pitch adjustment on the prop to adjust speed.
I think a few have already alluded to it, but beware the test ride on one of these....it's like a drug and the first hit is free ...after that you'll find yourself doing whatever it takes to own one...
Best Regards,
brando