Re: Do we have to implement customer specific requirements
Agree with all of the above advice, and will add that sometimes a customer's requirements are not soundly based in reality. Someone could invent the ultimate widget in theory, but if it's not manufacturable, it's pointless. Many times, manufacturer feedback can help the customer realize their product in a better and sometimes more cost-effective way. Some of our company's designs have benefited from just this scenario.
Talk to your customer and find out if their requirements are perhaps too rigid, and if so, why. They may be flexible to your suggestions. Or, they may not be the right customer for you.