Amp or DAC?

I’ve wondered about this for a while and was hoping for some opinions: 

Let’s say I compare the same company’s 75w into 8 amp and their 150w into 8 amp. Will I notice a difference in sound quality? If so, why?

If there is a difference between the 75w and 150w per channel amp can I narrow the gap or even exceed the 150w amp by using a better DAC?

Also, has anyone noticed that a lower watt amp has less distortion than a higher powered one, so throwing my understanding that the same manufacturer’s higher powered amp should be superior to it’s lower powered one out the window?