TLDR: If you have this rad/oil cooler combo, check your oil pressures ASAP!
I installed this on my'12 WRX GR a couple of years ago to improve reliability and prevent Boxer explosion.
Shortly after that, I installed an oil pressure gauge on my Killer B oil pan and was shocked to see low pressure after startup and during spirited pulls. And I recorded normal pressure cruising around!
I then went through the entire oiling system, found nothing out of place, and decided to bring the system to stock one piece at a time. Thankfully (or not), I started by disconnecting the CSF oil cooler. And guess what? The oil pressures were back to normal in every scenario I threw at it.
One track day later, I spun a rod bearing in cylinder one at ~56k miles. :(
Coincidence? Maybe not. My gut tells me the fluctuating oil pressure slowly beat up the motor, and sadness ensued. Unfortunately, others have experienced similar oil pressure issues with this radiator/oil cooler (searching the Internets).