Recently bought an 05' WRX. Love it just as my as my old 04' with 405awhp-420ftlb. Haven't had a suby in 3 years. My newer car came with 3 inch up pipe back exhaust ( stock headers). The stock engine management system is doing an awesome job regulating boost. The injectors are stock just based off sound( no loud ticking like my old 750cc pinks). I installed an Injen short ram a couple months ago-increasing my throttle response and spooling the turbo much faster than the stock air induction box. I believe the stock turbo (13t!?) is powering the boost which is at 14psi, I haven't had time to take it off and look at the serial number/part number. Since this was done by flat 4 performance in Illinois I'm sure they had it dynoed with the new up pipe back exhaust. Hoping I could get some insight because a tune is kinda expensive and there is nothing wrong with the car just seeing if a tune would be nessesary seeing that there is no problem in the management ( or I would see a check engine light, which I haven't).