I didn't spend much time looking but the megasquirt kit is in the few hundred dollar range? It would probably be the cheaper route to go, but more work to install. That said, i think it would probably be better suited for something like this. That is mostly a guess though as I've never really looked into the capability too much, I have just seen people running it on the turbo forums that are happy with it.
411 will also do it, you'll obviously have to buy a tuning suite which is a little more expensive. And then you can convert it to a 2 or 3 bar SD operating system.