Well, i haven't seen the new ones, but the original 4tec coolers had an aluminum base that had the two threaded inlets and three coolant channels, and a stainless steel lid bolted to the top. It was so you could open the thing up and clear the passages or replace the rubber gasket. The lid will be on top. Not sure if the new skis have a ride plate under the pump be the heat exchanger, or have integrated them into the middle bottom of the hull, like the seadoo spark. In any case, they should both be aluminum. Any welder worth his salt will be able to tell the difference