The connector from the alpine will not work on your new head unit. Your new head unit should have it's own partial harness.
Just cut the connector part from the alpine and match the wires to your new head unit's partial harness.
I've installed a double din monitor/dvd in my car and all I had to do was match the color of the wires. It may be a little tricky because the colors may not match exactly but as long as they're the same shade, it should work.
Thank for your comment on my car btw.