A used 30 dollar R1 regulator has been dead reliable for me. This pic shows how to wire it on a 5th gen. The fins were huge and had to be trimmed some.
Current Stable : 950SM Turbo! GSXR1000 RT-P1100 VFR800 RXC620 motard EXC520 CR500AF CRF450R Plated! CR250
Past stable : 90 +