The SBV’s are top notch. I owned a Shelby Blue SBV-550 and now own a SBV-800MF. Fantastic basses, very high quality and they sound great - really good pickups in them. In fact they are the best sounding pickups I have owned, including some very nice aftermarket ones.
As for advice on buying from Japan, I made a whole thread about it.
https://forum.bassbuzz.com/t/quick-guide-to-buying-mij-instruments-from-japan
I have seen SBV’s used in some of the stores in that thread (Shimokura in particular) but they are rare; I usually buy them used on Mercari.
There’s a tip in that thread about a broker here who will find, buy and ship for you as well.