Stage 4 Titanium Hardware Engine Bay Kit - Honda Civic Si (2016-2021)Location Diagram Our stage 4 engine bay kit includes 42 titanium bolts, 44 titanium washers, 8 titanium nuts, and 15 well nuts. The kit replaces the hardware circled in the diagram above. The Civic Si stage 4 engine bay kit comes with clear instructions that walk you through where to place each hardware piece, ensuring a fast and effortless setup. Locations include: Radiator Shroud Cover Headlights Core Support Fenders Radiator Stay Battery Tie Down