Martin,
Have you tried to put these in yet?
I have them installed on my car. There were no changes needed for the wiring connections, but physically getting them attached to the threaded posts on the underside of the dash was challenging. I could not get the tabs to bend the way they needed to on this particular set of speakers. I ended up making a set of small brackets out of some odds and ends from the hardware store's fasteners department. You can also use the threaded extensions as mentioned here if you can get your hands on some.