1. How will you do maintenance? If anybody qualified is allowed to fly it, there's going to be a lot of expensive wear and tear on it--do you know how much an engine overhaul costs on one of these? I'd be concerned about a "tragedy of the commons" situation, where everybody (everybody qualified for it) wants to fly as much as possible before it wears out or somebody crashes it.
2. How is this a startup? Specifically, what is the plan to make money or in fact do anything after the MiG is purchased? Sell maintenance as one of the requirements for actually being allowed to fly it? Or is it more "Help me buy a MiG so I can take it to airshows/sell rides, because nobody will come to Denver to fly it"? ;)
Anyway, this should be interesting.
Edit: I'd like to add that, based on some general figures I found online (max speed 2200 km/h, max range 1100 km, max fuel capacity 4380 L, all from http://www.flymig.com/aircraft/MiG-21/), you're looking at a minimum of several thousand dollars per hour to fly. I estimated that you could, all out, burn through a full tank of fuel in an hour at top speed, giving a cost of around $7000/hour at today's Jet A fuel prices.