[PaperBagger'14]

I've never done a sirloin tip, but I'd probably try something similar to a tri tip roast. Smoke it low and slow until it hits about 125f-130f, pull it off the smoker and get a pan for searing it filled with butter. Sear the outside and remove from searing pan @135f for a medium rare. Basically whatever temp you want your finished roast at, start searing it 5-10 degrees early