PTE GEN 2 Turbo Upgrade for EJ Subaru WRX/STi Select Options::With 15 psi Actuator The main difference is that

The main difference is that an AOS-"R" system "returns" what is collected back into the oil pan so there is no servicing required

16% thinner-than-stock tubes allow for more surface contact

Available for the front and rear calipers for the 2004-2017 and 2018-2021 Subaru STi models

you're probably well aware that a 3-port Boost Control Solenoid (BCS) is considered my most to be a 'must have' improvement before having your car tuned

PTE GEN 2 Turbo Upgrade for EJ Subaru WRX/STi Select Options::With 15 psi Actuator The main difference is thatDesigned to work with the factory exhaust manifold for a direct bolt on fit, Precision's Subaru factory upgrade turbocharger is the perfect choice for those looking to boost their performance without breaking the bank! Only available with 3 compressor cover inlet for maximum power. Vehicle Fitment: 2002 2014 Subaru WRX 2004+ Subaru STi 2004 2007 Subaru Forester Features: Exclusive GEN2 CEA 2 2618 forged aluminum compressor wheel Liquid cooled, dual