While the cider comes to a simmer, prepare the pork rub. In a small bowl combine the brown sugar, chili powder, garlic powder, salt and pepper. Mix thoroughly with a fork. Add the oil to the spice mixture. It will be the consistency of a crumbly paste. Pat the pork chops dry with paper towels, and then cover the chops on all sides with the spice rub.
Put the spice covered pork chops on the heated grill, and thoroughly brush with the cider glaze. Grill for about 6 minutes. Flip the chops and thoroughly brush with the glaze on the other side. Grill for about 2 more minutes, flip and brush again. Repeat this process until the chops cook for 10-12 minutes total, and reach an internal temperature of 145 degrees.
If you're also grilling apples, brush the halved apples with glaze and grill for about 5-6 minutes. No need to flip. Serve along with the chops.