cassette adapters work WAY better than fm adapters in most areas. So in some ways, you're better off with an older stereo than a new one if the new one doesn't have an aux input.
I've got a couple sets of heat sinks Justin did up for blue hawaiis that I could sell you for what he sold them to me for. I'd just have to dig up what he charged me. 1 set comes with rails, and both are tapped.