I am wanting go with a 4 " exhaust. First question stainless or alumized steel. Which brand is better for the price, what dealer has the best price, I have heard of Rips, but don't know who handles them. Magnaflow in the pro series has a 3 1/2" down pipe do they all? U. S. Diesel has the best price so far for Magnaflow. About any help would be great, Thanks