B&W 802 & B&W 803 Nautilus

Hi Everyone! I'm about to start looking for a used Nautilus B&W 802 or 803 and I have a question about the Amp. I couldn't afford the kind of Amps usually paired with these speakers unless I wait a few more years : ) I'm currently using an ONKYO Integra M504 to power my DM604 S3 and DM601 S2. I'm thinking about buying a second M504 Amp. so each M504 would power each B&W 802. Based on what I heard, B&W 802 are very power hungry and wasn't sure whether my setup would work.

Also, can you please advise me a thread to B&W 802 models because I'm not sure what I read is right or wrong. Are they made in the following Chronological order 802N, 802S & 802D ? Any information on used prices for both 802 and 803 would be very helpful as well. Thanks!