Basically you have two ways to do this, I did it on a 2000 S-10 a few years back, first option is buying a convertor so to say that changes the hi-volt output to RCA type signals, Crutchfield sells them for about 30 bucks, this is what I did and it worked wonderfully, I ran an Infinity Kappa 4-channel amp, front two channels on Kappa 4x6 plates and Kappa 6.5s, rear who channels bridged to (1) 10" Kappa Sub, great little system for an S-10 while retaining the stock head unit look. This will require cutting either your front or rear speaker wires just a few inches from the harness connector that goes into the head unit. The other option is having an amp that allows you to run hi-volt inputs, thus cutting your wires close to the speakers and running them directly into the amp, could be very difficult with the Xb as none of the speakers are very close together, I would go with the first option.