It's entirely possible that I've never tasted Aaron Franklin's barbecue sauce. Back when Franklin had his little barbecue trailer in French Place I ate there a couple times a week til the lines became untenable but never felt the need to besmirch the meats with anything: No sauce, no salt, no pepper, no ranch, no nothing.
When Texas barbecue is done right it doesn't need anything slathered on it.
The great pitboss W.B Brazil himself responded "I don't dope nothing up" when asked if he used any sort of mop on his meats.
Here's Aaron Franklin's Barbecue Sauce recipe via the estimable Yahoo website
14 oz. ketchup
5 oz. water
2.5 oz. apple cider vinegar
2.5 oz. white vinegar
4.5 Tbsp. brown sugar
2.5 Tbsp. Worcestershire sauce
1 Tbsp. chili powder
.5 Tbsp. Kosher salt
.5 Tbsp coarse-ground black pepper
1 tsp. cumin
Mix all ingredients in a pot and simmer until the flavors are well combined, about 20 minutes. Remove from heat.