I looked around for something similar and was very shocked to find nothing of the sort. So... I made one. I honestly do not have a ton of experience with Wikis, so if anyone has experience and would like to help administrate it, shoot me a PM.
Any contributions are greatly appreciated. From SQ to SPL to general information, I plan on eventually having a huge database that covers it all. Hopefully, it will eventually become a place that we can send newbies to do their research, rather than have them plague the forums with repetitive questions.
And without further ado, here's the link: Car Audio Wiki
PS: I had this approved by the staff before posting a link.