I have put an order for a Sadowsky Spec'd Single Coil 5's, so excited
When I suggest them to make me a set of underwind NJ5 pickups (less wiring) the guys at Nordstrand flat out said 'No' and told me that will only make the sound more aggressive as the high frequencies will be much more present that way. So, I guess Roger's Pickups arent made that way either.
And I also agreed that Roger has sucesfully made a perfect combination of pickups and preamp, I worked in a Sadowsky Distributor a few years back, a friend bought a set of Sadowky HC and a J Retro preamp from me, and install them to his Mexican Fender. But the sound is not quite there, then he bought the Sadowsky preamp and wow... It changes everything, the same guy bought another set of the Sadowsky preamp and install them on his 2012 American Deluxe Fender with the N3 Pickups, and it also work wonderfully
So I guess Roger's Preamp can work wonderfully with a lot of different Pickups, a lot of people I know have install them with success. And I agree that it's a very BIG factor on the 'Sadowsky Sound'. But for the Sadowsky Pickups ,IMO they need a Sadowsky Preamp to be able to really shine, not any preamp will do, but again, back to each persons need/taste.
And again, on the whole Fender vs Sadowsky thing, it's funny for me, coz they look almost the same (my MV5 and '78 Jazz), both sounds like Jazz Basses (of course), but everytime I play the Sadowsky I was like "I miss the 'thuddy' thump my Fender has", but everytime I play the Fender, I'm like "Damn, why can't this thing cut through and just 'stay there' like my MV5"

That being said, I'm happy to have both