Photographing FIRST Competitions

[Dan 1038]

For all of you "REAL" photographers out there, I am curious as to how you shoot FRC events, specifically settings and equipment. I am an amateur photographer who has been shooting FRC for 4 years and think I get decent results (see www.frcpics.com for examples), but I am curious as to how others approach the challenges of low light coupled with action and reflective surfaces not conducive to flashes (ie the driver windows). Below is how I do it:

Camera: Canon 40D
Format: RAW for Saturday, LJPG or SRAW for practice and qualifications (mostly for scouting, saves space on the PC and cards)
Lens: Sigma 50-150mm f/2.8 DC HSM II (Best bang for the buck)
ISO: 800 generally, but some venues have forced me all the way to 1600
Short Lens: Kit Canon 28-135 f/3.5-5.4 (hate it, shopping for something around a 17-55 f/2.8)
Flash: None (Shopping, considering Canon 430EXII or Sigma EF530)

The challenge, as I see it, is getting the right aperture and ISO combination to allow the 200+ speeds to stop the action. Is this along the right track, or am I missing something??? Any recommendations on a short zoom for general shots (like team portraits and wide angle field shots) or flashes? As this is a hobby to me, I have a problem dumping >$1000 for a lens or >$500 for a flash, if I can get similar results for half the price. The Sigma lens is a perfect example, it was around $800 - almost half the cost of the Canon 70-200 f/2.8 at the time - and on a I get the bonus of it being smaller and very effective. I appreciate any responses in advance!