Treadstone Performance Engineering Rated-R Intercoolers are mainly used on side mount twin turbo applications where you can sacrifice ambient external airflow because there isn't a radiator behind each core that requires airflow. By eliminating the radiators need for airflow, Treadstone is able to shrink the ambient fin height, and add this to internal flow. These Rated-R cores will also be found on full race intercooler set ups on large front mount intercoolers.
This R core, with the standard bar height, is rated for 1340 HP and 2010 CFM while the normal C1245 is rated for 980 HP and 1469 CFM. (22" x 12.5" x 4.5"). With 22 internal passage ways compared to 18, this core allows higher internal flow and less pressure drop.