without a doubt. the stock ecu is limited at about 17 psi and i dont think that Subaru would have set it that high if it would hurt your motor. i ran 16.5 psi with only an intake, axle back exhaust and boost controller for a long time with no problems.

 

15 is quite safe... but there have been people who's run 15 and experienced detonation. Who knows what these people were doing (like loading bad gas or 87 octane by accident) or what flukes they had in their ECU. 15 is quite safe... but there's always risk. If you want to run 15 PSI, just be gentle about it. Don't put in an MBC or EBC and mash it. Like when I first put on my sway bar I didnt just drive off and start taking corners at insane speeds. I swayed on a straightaway first, and slow corners, then faster and faster. All car parts deserve the same tender lovin' care

As far as max, my ECU cuts at 17.8PSI. I think it's MRT (?) that says the stock turbo (and internals ?) can handle 19-20PSI. Of course anything about 15.5 or 16.0 does you no good but to give you a heat soaked turbo and a heat inflated charge.

jason

 

MBC= manual boost controller
EBC= electronic boost contoller
MRT= Middleton Rally Team- a Subaru aftermarket parts manufacturer based out of Australia