I've done it. I've changed the pickups and had a refret done on my 56 NOS Strat. I was getting thoroughly fed up with over-loud G and the too quiet top E. (I use 10s with a plain G. I freely admit that I'm a wimp!) I noticed that the Fender Pure Vintage 56 Strat pickups have the original 54-56 magnet stagger with a lower G pole and higher top E pole, so I thought I'd give them a go. They've cured the string imbalance, and also give a warmer sound than the original pickups, probably due to the fact that they use Alnico 3 magnets instead of Alnico 5. I know the Fender CS pickups fitted to this model are meant to be good, but in my opinion, the Pure Vintage 56 pickups blow them away.
I had the refret done because, even when new, the vintage style frets were incredibly low, and I was fed up struggling with them, having to use more force than should have been necessary to press the strings down, and I couldn't get more than a semitone bend without the strings choking on the upper frets due to the 7.25" radius. I had it refretted by Pedro Martins of Guitar Repairs Brighton, www.guitarrepairsbrighton.com. Pedro has worked absolute wonders. The fretwire he used was the equivalent to Fender's current production gauge, and he also took the shine off the neck and fingerboard, giving it a more 'satin' look and feel, so I no longer suffer with the nitrocellulose 'sticky neck' problem. This wasn't a drastic change, just a light going over with some 1000 grade wet and dry. I can't believe the feel and playability of the guitar now. The only downside to this is that I can't blame the bum notes on the guitar any more! If you're in or near Sussex, and need a guitar repaired, I can't recommend Pedro highly enough.
Simon