The wiring is already there, under the carpet; I think I spoke of it in the directions you used. There's an X cut in the carpet slightly inside the right front corner of the seat brackets. If you unbolt the seat so you can get the sub underneath, it's easy to lift the edge of the carpet, find the connector head, and feed it through that X. All cars are wired the same.
A Radio10 is a little nicer than a Radio9, giving 6 disks worth of capacity and slightly better MP3 disk support. Many people upgrade to a Radio10 when they find out how inexpensive they can be found.