I've passified my SubRay4..... and it's great. I put in a switch for 'series/single coil/resistor reduced series' as series/parallel caused too large a change in output. With this switch, and going in to a DIY Barbershap, I can go from clean through slight break-up to more noticable grit. I'm very happy with it.
p.s. I used a GFS MM-pro p/up.