When something is referred to as 'stellar', it means 'star like', sort of a play off hollywood stars and critics language when speaking about them. Astronomical.
To be over the top, is like saying 'it's too much'. Like someone wearing a tuxedo to a picnic. It may look good, but it's not appropriate. When I used it earlier, I meant that it would really make it look great. A lesser version of 'it's too much'. A more slang spinoff, like someone saying 'I'm bad.' I really means I look good.
