I've got an rg4ex1 too, and the pickups definitely need to go. I dropped a set of EMG's in mine and it sounds great, but I wouldn't recommend that so much for you. I use the guitar in a death metal band. For alternative/rock/hard rock I would go with either the
Dimarzio Tone Zone or a Duncan JB in the bridge, or a Dimarzio Super Distortion if you want it a bit hotter. In the neck I'd go with the Dimarzio Air Norton or a Duncan Jazz or '59.