As you guys know I am very eager to change my current registrar and going to much cheaper yet simpler one. So, here is my query which I am really worried about? Will there be any downtime?
If you do it right then changing only a registrar shall not create any downtime.
I did it. Didn't create any downtime. Although I have faced some problems as I forgot to remove the WHOIS from my domain.
Is removing WHOIS mandatory?
Transferring domain registrars should not result in website downtime if you manage the Domain Name System (DNS) settings during the transfer correctly; provided your nameservers remain unchanged, your site should remain accessible during this process.