Great Question.. I think the CDR-24 is all MOST Optic Fiber with the Amp, etc.. (and probably to the instrument cluster too), I heard any modification to a component need to be programmed at the dealer..
I think you'll have alot of trouble to just to change the Head Unit without changing the Amp and All, and I would be surprise if you could still feed the instrument cluster info Display..
But I'm not very informed about the CDR-24 modification, I spend more time on the CDR-220..
Good luck in your project/search, let us know because it's a very interesting question!!