You can run 10lbs of boost on stock injectors with a 12:1 FMU and inline pump, but it'd be better to run some DSM 450s with an AFC, or even better to run a standalone unit. Checl valves are typically put between the throttle body and the MAP sensor with an FMU setup. You either piece together some tees and sections of vac hose for the fish tank type valves, or screw an aluminum check valve in between the tb and MAP sensor. A check valve is not needed for a 450/AFC setup up to 10-12lbs of boost, nor is it required for a standalone unit.