Hi Shaily, I've seen puppies which belong to imported parents are rated very heavily. Same is a case with puppies with registration papers. You mentioned puppies with KCI papers for rs 8000 and 7000, thats very surprising. Are you sure they are KCI registered? Just check that again. It must be puppy registered with local kennel club not KCI registered because a KCI registered puppy costs 5000rs more than a non registered puppy. If you are really being offered a KCI registered puppy at this price than go for it! but check if it's KCI registered or local kennel club registered.
One prefers a KCI registered puppy just to insure that parents of the puppy are also of the same breed as that of the puppy. KCI defines the breed standards and certifies the dog only if it meets the breed standards.
This is the only rationale behind preferring a registered puppy. If you can't afford a registered puppy then it's ok to buy a non registered one but make sure you have a look at the parents of the litter. Make sure puppy is not younger than 8 weeks. Before you take a puppy home, make sure no liquid is coming out of their eyes or ears. Offer some feed to it and if it comes happily to accept it, then puppy is most probabily healthy but it's advisable to take puppy to vet before you take him home.
Try not to buy puppy from pet stores as they are kept in a very sorry state, try to buy from a breeder.