Definately 4 collector. The Bebes will be better late game but you NEED a Collector early to get set-up and running 4 increases your chances!
I find Vilegar too hard to tech. You need 4 Spiritomb, 2-2-2 Vileplume and at least 4-3-3-1 Gengar by which time you have very few tech spaces left. Boo etc!