I just looked it up and a ViaAqua 2600 puts out 400gph at 4' and about 350gph at 4.5' which is what I am looking for, guess I found my pump! I would go with a mag 5 but they get to hot, I have heard..
You use whatever pumps you like that give you the desired flow for the application youre using it for- theres no wrong answer really, I like marineland pumps because the impellers they use are of good quality, are stiffer than some and are curved to have better flow- whether its 100% true or not i dont know- but Im a trusting person..
Just remember that for every 90 degree whether made up of 2 45s or straight 90's you have to add 2 feet of head to calculate for proper flow.
Choose wisely with something youll be happy with and go with it. Youll be good to go.