We build the radiator in house. The E-Series unit uses different(14”) fans, overflow tank, and the radiator is American bought not built. We redesigned the core support to reduce costs, but still retain function without some of the aesthetics. The AC condenser on the AutoRad unit is $250.00 (full cover is $350.00). The AC condenser on the E-Series is a little different design and is mounted different so that it can be added later if needed. The trans cooler on the AutoRad unit is an internal tank design. The E-Series trans cooler is a radiant fin design and mounted externally so that it also can be added later if needed.What makes the E-Series unit different from the AutoRad unit? The difference is in the detail.