Side Under Spoiler
1. Clean the surface of your Si's sides with isopropyl alcohol, where the side under spoiler attaches to. Use a tape measure and a felt-tip pen to measure and mark the areas where you'll be mounting the side lower bracket to (refer to instruction manual for exact specifications). |  | 
2. Carefully position the side under spoiler to the chassis -have a friend help; it'll make life easier on you. Remove the adhesive backing to the mounting tape and attach the side under spoiler to the car. Make sure you align it properly with the installation bracket panel, then secure the spoiler to the car with the provided self-tapping screws. |
Rear Under Spoiler
1. Remove the rear bumper from the chassis and prop it up on a stand so you can cut into it. On the inside of the bumper, there are 10 preset marks to help guide you, just like the front bumper; punch through them and remove any burrs from the edges (refer to instructions for the exact holes). Cut out the rear bumper along the exhaust exit area. |  | 
2. Attach the clip nuts to the bumper and install one square head bolt into each slot under the rear under spoiler. Remove the adhesive backing from the spacer and attach one spacer over each square head bolt. Install the rear under spoiler to the bumper and use the supplied self-tapping screws to keep it secured. |
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Great success! The HFP under spoiler/aero kit fits like a glove. Additionally, we upsized the factory wheels to the 18-inch, gunmetal HFP optional wheels with Dunlop rubber. Offset-wise, the wheels could stand to stick out a little more now that the body kit extends the lines of the car out. We'll most likely solve this problem with a more aggressive set of wheels in the future. For now, we're happy our upgrades stay within the factory warranty guidelines.
Penske Supports You
Believe it or not, Penske and many other Honda dealers across the nation support your cause to modify, whether it's within the Honda family or with products that keep in line with keeping our air clean. Penske not only stocks the entire HFP product line, but plenty of other street-legal performance products that will keep you from getting pulled over. Best of all, any parts sold through Penske - HFP or aftermarket - are fully covered under and will not void your warranty! (Please check with your local Honda dealer to see their policies regarding aftermarket accessories.)