Q. Can I fit genuine Honda DRL in S CVT variant of Honda Amaze? If not, then whether aftermarket DRL is recommended or not?

No, You cannot fit genuine DRL because Honda will not allow you. This is stupid policy of Honda. They will maintain the trim difference so that people cannot buy a lower priced version and make it look like premium version. The reason they claim is that DRL are only tested for higher version. However it is obvious that if they allow such modifications then it will impact the sale of higher version as everyone will buy lower version and customize it to make it look premium causing losses to the company. Moreover aftermarket electrical modification are not advisable as it will void the warranty on electrical parts. Honda offers 3+2 year warranty which can be extended till 10 year. Loosing the warranty is definitely not advisable because you never know when you may need it. In future even if the damage is not related to your modification, company will put the blame on the modification and you may end up paying heavy price for the cheap after market modification