Hi,
Refex Pro Acoustics is the authorized dealer for Marantz in India(there is reference to the same in some threads on this site and some other places on the net).They offer 3 yrs warranty support for the A/V receivers. I am not sure about the after sale support though, also as they are located in Chennai, you need to send your equipment to their workshop.
Earlier Sharda Motors based in Delhi used to be the official dealers for Marantz products(you will find that they still stock a lot of 4002/5002s and claim that only this series is officially available in India). These guys provide 1 yr warranty.
The other dealers are basically all importers who get the stock directly or through a 3rd party and provide after sales support themselves.
So If you are purchasing from one of these guys and are looking for after sales service choose a distributor which has good technical support team or links with people who can get the equipment repaired..
Also the link mentioned in the previous post, the contact address shows a email id as:
[email protected], which gives the feeling that the owner of the site has a shop and not a company.
My first choice was always Marantz (wanted 6003, but was getting 5003), but choose Yamaha (863) instead as these guys have official support center in Gurgoan, which is nearer to my place.