I installed the hardwire kit today. Everything went well until it came to installing the add a circuit part. I absolutely could not do it. It took me about five minutes to route the wires through the headliner, down the A-pillar and under the dash. I spent the next three hours trying to get the Add A Circuit to plug in to the fuse block. By the end I was drenched in sweat and frustrated to no end. So I went into the house, cooled off and drove to a local stereo shop and had them complete the install. The camera comes on when you turn the car on, which is what I wanted. Overall I'm very pleased with the camera, with its performance and configurability, and pleased with the hardwire install. You can see about five inches of wire going up to the headliner. That's it. The rest is hidden.
Now I have to decide if I want to install the CPL filter. I want to get some night video before testing it, to see if it blocks too much light at night.
I went down the Chinese American Community Center with my warranty card and the instructions for the CPL filter, both of which are in Chinese only. The lady told me the warranty is for one year, and you do not have to fill it out and turn it in. The instructions for the CPL filter say to clean the lens with a wet wipe (provided) and then dry it with the dry wipe, before installing the CPL, which is a stick-on filter. I think I'm going to tape it to the camera for testing purposes before permanently affixing it.