Port Injection requires a significantly richer AFR target than Direct Injection under load. Where you might run 12.3 AFR on DI you would want to run closer to 11.3 on PI. Make sure you or your tuner are familiar and experienced with tuning port injection engines or engine damage may occur due to improper tuning.
Direct Injection provides more knock resistance than port injection so be careful when running on lower octane fuels and high boost. In our testing with ethanol blends we did not need to reduce ignition timing at all when compared to direct injection.
Port injection may require a 5-10% increase on cold-start fueling for a faster engine start time.