I picked up one of these quite recently and have had a similar dilemma.
For the absolute piitance I paid for it, I couldn't refuse, but I have wondered about how to soup it up a bit.
The old Yamaha pickups were a bit tame.
I feel it could make a nice "faux-cabronita" so I started with some hotter HBs and some cheap H style covers.

But now I'm thinking about putting a pair or HB sized P90s even.
These early Yams are good modding bases IMO.