I'm putting together a new rig. I've already decided on Avatar B210 and B115. For now, I'm going to power these with a Carvin FET1000 (our sound man has one I can use indefinitely for no cost). I already own a Sansamp DI (stompbox). Can I use this as my preamp or should I buy the RBI? Any other suggestions for other preamps (for around $300)? Should I buy the 8ohm cabinets and run the amp mono bridged 1000 watts @ 4ohms or buy the 4ohm cabinets and run the amp stereo 500 watts/channel @ 4ohm? I currently use an SWR Workingman's 15 combo, which I thought was great when I bought it but now I'm terribly underpowered. Our lead guitarist recently bought a 100watt Marshall stack. I think he's trying to compensate for small equipment elsewhere.