Okay, another thought on Anti-lag options -- what about a variable nozzle turbo - ala the VW/Garrett VNT Turbos??
It isn't a anti-lag system, but in theory, you get full reliability but with better spooling characteristics --
Turbotech - Australia's specialist in turbochargers - Garrett Turbochargers
But really, what you want fred, is a supercharged, variable-nozzle turbo, with dual wastegate/bypass setup, along with nitrous, and CO2 spray on your intercoolers --- then you'd get instant boost - all the time, and massive power...
and a very very light wallet, a weight reduction which will undoubtable help.
Seriously, I like that dual waste gate idea. It would seem to me, that you should be able to store the waste exhaust gasses somehow, and re-use them to keep the turbo spooled. It would require that you start the car up, and have it running for a little while, to buildup pressure, but then once the "bypass storage" container is full, then you'll get your anti-lag effect, via the second valve....
I don't know how practical. You'd want to keep the exhaust gases hot.... and the timing on the valves will be rough... you'd almost want to set things up so that it is always overboosting, so that you'd have something to go into the "bypass storage" container...
I'm imagining some crazy U-shaped pipe, with a bulge in the middle, and two check valves, one on each end. On one side it is connected to the main waste-gate, that would be the input to the "bypass storage", and the other end goes to the exhaust manifold before the turbo - almost like a fifth cylinder.... definitely custom manifold time. When the pressure is too low in your exhaust, it would open - and you'd get the contents of the "bypass storage" into your turbo...
Somehow, I don't think it would work very well.
I'm still voting for a Supercharger added to the system.