Vanderhall 1.4 turbocharger upgradeBlack Widow Turbo stage 2 I chose to have a 55MM billet impeller be the heart of this turbocharger. The turbo is designed to direct replace your OEM turbo without having to modify anything. The one pictured on the site has been bench flow tested at 150,000 and 200,000 RPM. It tested at 18 23 PSI. I recommend if your running any higher boost to change your valve springs to something stronger. The OEM springs may cause valve float over a certain boost