It will do 300 but keep in mind that if you plan run that on a DD that the turbo will fail prematurely because of heat and RPM like SLO said. I second the notion for the Evo 16g, it will support 350 all day and live to brag about it.

 

My motor stops making power past 5500 RPM's, it's a 8 valve. I'm thinking the small 16g might be a better choice.
I'll be running e85, seem's to help cool down the charge while giving you 100+ octane, and I have 8:1 CR, so I'll be daily driving on no less then 20psi