These are all good guns but in my opinion the PX4 storm is the best of the bunch. I shot all these and more trying to figure out which gun was right for me. It comes down to this. Buy the gun that feels the most natural in your hand. That will be the gun you should buy. Kames had the Storm on sale.
Looks awesome Brian good for you. I actually had the pleasure to meet and ride with a guy on an RC51 Bill Riviello who had the same set up on his track bike. He used velcro on the soles of his feet instead of the straps to keep his feet in place. We rode VIR and he was actually still very fast on that bike.
Buy some Yamaha carburetor cleaner dip. This stuff is awesome! Take the carbs apart and dip them in this water base solution over night. Its amazing how well this stuff works. http://www.yamaha-motor.com/outdoor/apparel/apscitemdetail/3/124/all/4/322/detail.aspx
for what its worth I would go with a 60 gallon tank. Look at the tools you will be using and find a compressor that will run all the tools. Also a compressor that runs on 220 is much better.