Best tanks for CSM

So quick question, ive got a decent chunk of infantry unita and forgefiends/maulafiends now for my army.

However i dont really have anything to tackle high toughness vehicles, so which is the best anti vehicle options? I was debating getting a predator and a vindicator tank. Should i get one of each or get 2 predators?

Any help would be greatly appreciated for debate for those with more experience then me