My biggest concern would be how these differ tonally from a true single coil. If you are going for a tone that is "vintage Strat, but hotter", this may be a problem, since these are clearly not single coils, even though they fit into the same physical space as one. They're humbuckers and can't reasonably be expected to sound exactly the same. But if you're really not concerned about that and just want hotter pickups to fit the existing routed cavities, then maybe you don't care much about such tonal character differences.

I'd strongly advise looking for some sound samples of these or similar rail-style Strat pickups and see how you like 'em before you go ahead and order. I don't know if GFS has sound samples, but I'm sure DiMarzio or Seymour Duncan would have them for similar models.

I'd certainly consider the fact that they are 4-conductor p'ups that can be "wired up fancy" to be a plus!