One of my favorite karaoke songs Locked Out of Heaven by Bruno Mars. I can sing it, but I'm definitely pushing the limits of my range, as I get tired towards the end of the song. Will this course help me increase my range to sing that song comfortably in the original key or should I be pitching things down? I'm hoping the former since a lot of pop songs nowadays are in those higher keys and it'd be hard to find pitched down versions of all of them!      

Hi, Vof! While I can't guarantee it, I do think you'll increase your range with consistent exercise. How much? I don't know! My recommendation is to pitch songs down to the point that they're almost comfortable, but a little bit of a stretch. Over time, as your range grows, pitch them back up (1 half-step at a time). 

I know it's frustrating, but your voice may have a different "sweet spot" than Bruno Mars, and that's okay!