I don't, that's Sewell's trick but it's nothing more than a buck-boost regulator with some ass behind it. Not a bad idea, that.
My only 1600cc experience was with an FJO driver box; they wouldn't idle cleanly, precise injector control at idle and light throttle was complete shit, they were taken off and shelved.
I've nothing against the Injector Dynamics stuff, but I haven't had any problems out of plain jane Precisions. The cars idle smoothly, and make 600 to 700-something whp off of a set of four. I can deal with that.