I'm new. I don't have much idea or knowledge about hi fi. But i had a Pioneer VSX-D902S and Advent Heritage speakers. I'm looking for a good integrated amp and speakers. Do NAD 3020 and Xavian speakers could be best to here the music?
The NAD 3020 was very good in its day...it's a recognized classic...but probably not something that is going to beat the budget integrateds of today. It seems like the current model C315 would be the better way to go.
It's somewhat common to discuss budget integrated amps or even budget separates here, so it may be that you'll find there are other options you would like to consider. In recent times here, we've discussed the Cambridge Audio 340A, the Rotel RA-1060, and a few others. Adcom separates can be found in this same general price range on the used market. An example would be a combination of the GFA-535 amp and GFP-555 preamp.
As for speakers...I find it more subjective and it's not a subject about which I have any level of expertise, so I find myself asking speaker questions around here rather than answering them. That said, I'd think you'll get some good input here on the topic...especially if you'll describe your listening environment and preferences.