Here's a very nice (expensive though) hitch that is made for the Prius c. It seems to be very well engineered and stays out of the air flow. The manufacturer is located in Kent, Washington. Torklift Central - Toyota Prius C Trailer Hitch |EcoHitch|Seattle|Kent|Auburn|Puyallup|Tacoma|Renton|Covington|Sumner|Bellevue|Burien|Enumclaw|WA Move down the page... they have a video of the installation on a Prius c.
Just for the record, you're allowed to tint your front windows in CA, but with minimal light blockage, so the "tinted" window will look clear to the eye (70% of light must get through). See Welcome to TintLaws.com. On the back windows, anything goes. I've wrestled with the question of tinting, in that I like the privacy of darkened windows, but I don't want impaired vision, especially since I often drive at night. But I understand the low-level tinting provides UV protection, so the car will be less of a hothouse if you're in a sunny climate. That is to say, even the subtle tints serve a purpose.
Having made many chassis braces for the Gen III and Prius v, a number of Priuschat members asked me about making one for the Prius c. The Prius c, in all versions does not come with a mid chassis underbrace. I've seen only one individual car that had one from the factory. I'm posted photos of the underside of the Prius c chassis and my Ver 3 "c" brace. I believe this to be the best available. In making it, I looked at the construction, engineering and installation of the expensive one made by Cusco, as shown on the JuicedHybrid.com web site. http://www.juicedhybrid.com/Prius-c-Power-Brace-and-Chassis-Brace-p/949-492-c.htm http://www.juicedhybrid.com/v/vspfiles/assets/images/949%20492%20c_eng.pdf The Cusco model is heavier and made of three welded pieces. Welding weakens the hardening of the tempered aluminum components at the joint. Installed, my brace adds a mere 10 ounces of weight to the car. My virtually "bulletproof" brace is made of a single piece of tempered billet 6011-T6511 aluminum. The ends and counterbores for the included 10.9 grade better than OEM flange bolts are J.I.S. with 12mm hex heads; the same heads as the factory bolts on the car. The center section of the Cusco brace reduces clearance for the exhasust system. Mine provides maximum clearance. The "hangdown" of my brace is about 1/2 inch, which is about the same as the Cusco's at the mounting bolts. Both mounts with two bolts. There is no advantage to the additional "contact points" that the Cusco brace makes with the tunnel. The paint or coating on the Cusco brace is for looks only. The aluminum alloy on mine is corrosion resistant on its own. The complicated construction of the Cusco brace apparently is to justify its high price. That's about it!