How much power are you aiming for?
They have nothing before 4 grand anyway just get a TD06L2 20G 8cm (like $799 from the kando or a billet one from hypergear), a few people have said they have moved from something like a 2530 to something larger and not noticed much difference.
But it depends what you want if you want a whole highmount setup or if you want to keep it as stock looking as possible etc etc.