I bought a piece on impulse and now have a few doubts about its authenticity & value. The good thing is that the payment has not been made. I would be grateful if the friends here can give some comments quickly. I need to make a decision in 24 hours.

The piece is bought at a retail shop at Shanghai, China, which is run by a British couple. They are now closing the shop and moving all the remaining stock to Singapore. The Nain piece is said to come with a certificate which I didn't get a chance to check and its KPSI is 520 (?). They are asking for CNY 27,000 (USD 4,000) after a 50% discount. With the information I got from this site, I guess it is way overpriced, is it?

Since I am now on a business trip I cannot take the pictures as guided by this forum. Sorry for the insufficient materials for your judgement. Below are the link to the item and some pictures I took with my mobile before.

The link: 33418 Nain South Persia

The pictures:

One thing that bothers me is that the design looks carelessly woven with jagged "straight" lines visible in my picture. Is this a sign of low quality?

It is a medium quality Nain, not very fine, I would guess rather 160 to 200 kpsi from the pictures. A regular store price for this would be arround US$ 2500 - 3000 since it is a new rug. So if you get it for somewhere around $ 2000 it would be ok.