The March is under $800. The Billet Specialties is $2500, plus about another $600 for all the stuff they don't tell you about upfront that you will also need.
The Billet Specialties is a lot more, but it is also a lot nicer looking and includes more. Frankly, I don't like the way the March system looks. I'd rather spend the 3K on the Billet system than 1K for the March. Maybe if I ever do a resto-mod, but I think I'll pass on my current car.