Rate my pearl Pokemon team and suggest a 6th team member?

Spiritomb is really good. He has no weaknesses and is super effective against some tough types plus normal and fighting type moves don't effect it. The only problem is you need to talk to 32 people in the underground(Basically get another game copy and go into the underground talk with the copy leave go back in talk and repeat 32 times.) The process is tedious and also well worth it. If that doesn't work go for a gible and level it up because Garchomp is really good(he's even considered pseudo-legendary).