Outer Limits 4x4 Board

ok guys time has come replace the radiater to behind the cab in the lux, what im afetr is what type of inline pump are you guys running should i up grade my radiater, it a brand new one is running fine so i can use this or should i go larger, where's the best place to run plumbing material to use. stanless pipe/ally pipe and normal radiator hose bends etc?

any help would be needed