I would not use a double or triple pass radiator for the street. There is a big misnomer when it comes to "keeping the coolant in the radiator for a longer time so it cools". The problem is this.............if the coolant is sitting in the radiator for a longer time...what's happening for the coolant waiting to come into the radiator? What is happening is the coolant in the block is getting much hotter.
You want coolant to keep moving in the system. The better it moves, the better it cools.