It has two main engines - and a nominal SOI will see it just use one for the whole burn. If there is a problem with it - it will automatically switch over and start using the other engine, and indeed, would switch back if the situation prompted such a thing. Chances are it'll be just one long clean burn from the one engine that's worked perfectly for a lot of accumulated burn time already.

It will use the moons ( well, Titan ) to shift it's orbit, but also it's main engine, and the little thrusters it has as well. Infact, in a few months after SOI, it will do a long burn to raise the low-point of the orbit so it doesnt encounter the rings every orbit. Looking at the flight path pictures you can see the orbit change during that burn, an unusual characteristic in space flight.

Doug