I'd be in the market for one of these adjustable FPRs myself. Between the 19lb injectors, 62mm TB, and intake changes I made a while back, an adjustable FPR probably wouldn't hurt.
But let's say I get the adjustable FPR in there and all set up and the A/F ratio dialed in using a gauge of some kind.
I am still considering wiring in an adjustable MAP also (I know you can build the thing and the retail version is way over-priced). Am still not clear as to whether adjustable FPR makes the adjustable MAP redundant as a means to tune the AF ratio.
If you put an adjustable MAP setup in there with the adustable FPR already in place, are you going to end of throwing the AF ratio out of whack again?