Boost kit for sure. Longer control bore. Also look into the fuse like redriot recommends. Might save you money if you can snag a single bore, but if the kit is only a little more then go for it.
Nothing wrong with ULs, they're solid barrels. They are just overpriced, and plenty of comparable/better barrels can be had for WAY cheaper. CP one piece and lurker come to mind.