Please note that specific setup and pricing may differ from each customer. Our Stage 4 (previously stage 3) upgrade was developed for our customers who want to run 10 second quarter mile times and beyond supercar levels of performance! The Stage 4 power upgrade for the ISF Supercharger kit achieves 650whp to 714whp on e85 fuel (about 760hp to 860 at the crank @ e85 content of 70-80%). Internally stock ISF engines are recommended to run 50% e85 blend or higher for maximum safety/reliability. Stage 4 upgrade kit includes in most cases the following (may differ depending on application):