For the MARINADE;Combine all ingredients except BBQ sauce: mix well.Place roast in a plastic bag: add marinade and seal bag . Refrigerate over night,turning occasionally.
Grill roast over medium heat using flavored wood chips(soak for 2 hours in water or beer i use a dark beer). Grill abought 25 minutes per side for medium. Baste with marinade combined wih 1/2 cup BBQ sauce. To serve cut into thin slices.
WHISKEY BUTTER: Combine all ingredients except butter,mix well. Bring to boil in a large sauce pan and cook for 8-10 min,reducing by half. Remove from heat. Add 2 or 3 pieces of butter at a time, untill all is blended in.Serve at room temperature with grilled roast and peppers