i was looking at this a while back. Not sure about the flow rating though. The 24v is taller, . . but has less tubes in it. The reason the 24v is taller is because the fins are taller. The reason Piers said that the 24v is better is because the coolling is better, i guess because of the fin count or fin height, not because of flow. Actually the slower it flows the cooler the air will be because of more time in the cooler. The main restriction is were the inlet and outlet sweep around the radiator. Piers said an average a 50 degrees difference between the two and u want every little bit u can get. So then i would get the 24v, BUT this is just not the regular 24v u want, ..... u want the one that is NOT painted! i think the 2001 and up. This does make a diiference. I would like to compare a 12v intercooler not painted and a 24v cooler not painted. oh well one of these days when i'm not busy, lol.