Billy, comparing a Crown Head to a Marine Elegance is like comparing a Model T Ford to a new Lincoln. Both will get you where you need to go, but one will do it in a far superior way than the other. A Crown Head can be converted to operate with pressurized onboard fresh water. I had a "sticky" on the front page of this Forum describing how to do it but it evidentally has been taken down. Les will sometimes do that when he's looking for space on his hard drives.
Anyway, if you want to convert one, contact Jerry Amari at Raritan (800) 352-5630, ext 236. He can fax or e-mail you the instructions. Parts to do it will cost, these days, around $300 if you buy them from Raritan.
But as Billy mentioned, why spend the money on upgrading a dinosaur? When all done, it'll still be a dinosaur.
The Marine Elegance is nicer, better-looking, cleaner, quieter, uses much less power, and is less expensive than the Crown Head - especially if you get the pressurized fresh water version. Plus, you'll get the larger household-size seat and bowl - the Marine Elegance is not available with the smaller (marine-size) seat and bowl.
Boatfix has 'em in the $600-$700 range, depending on which specific one you want. If you have any questions on which model number you need to order, call Jerry (phone number above) and he'll be glad to ask you the necessary questions, then give you the specific model number for the one you want.