I need to know more about carvin guitars

I posted the last thread about the guitars i was looking at buying. Scince the time I posted that I got to play my guitar teacher's carvin but not for that long. It was a dc127 I think. It felt really comortable but I still have a couple questions before I order one. My teacher and I were working on something fairly slow when i got to play it, so are they fast? do the coil splitters (make humbuckers sound like single coils) work that well? Do they last? what are the better models, and what are some good upgrades? I have about 700 to spend and this is what i think I want. The only thving I plan to change from the standard is the finish on the back of the neck will be tung oil.