My 2004 SUBARU IMPREZA WRX/STi HD

This is my 2004 STi equipped with a APS tmic, APS S/R40 turbo, 800cc DeatschWerks injectors, INVEDIA 3"turbo back exaust. conservatively tuned to 22psi with 91oct fuel at True Tune Subaru Performance in Woodscross, Utah. my car gets 18mpg if I stay out of the boost but I get around 12mpg. Two JL audio dual vc 10" subs in custom built enclosure and a 1000w alpine amp. 4 6"mids with a 800w 4ch sony explode powered by a 2010 JVC camillion deck