The B&M cooler is of a stacked tube design. Meaning all the tubes would have to clog before it quit flowing. Unlike single tube coolers such as the stock version that once they clog the flow stops. Because it is a stacked design is it made of some pretty heavy gauge aluminum and does not have flimsy fins to bend. I bypassed my stock cooler because is was also clogged meaning no flow. I also replaced the filter to prevent my B&M cooler from clogging. The way it regulates the level of cooling is by allowing for fluid to flow through more of the tubes as the fluid thins with heating. Hard to explain in words. Instead of fins the tubes are profiled to increase surface area and also move air over more of this surface. I chose to mount mine behind the engine cooling fans because my thinking was if the engine fans are on the trans would need cooling also. Like I said, the Subaru service manager had no problem replacing my transmission under warranty after seeing the set up.

John