'Let's Go' is my favourite track followed by 'Man Enough', 'We Belong ' and 'Dangerous.

The order in which the member member sing on 'We Belong" are

Verse 1
Joe Elliott: first line, all chorus
Phil Collen: 2nd line
Rick Savage: 3rd line
Vivian Campbell: 4th line

Verse
2: Rick Allen
and so on.

Vivian and Savs vocals sound quite similar. Nasally. I think Rick's voice may have been digitally pitched to fit the song as his voice sounds a little bit electronic.

As an aside I found a demo of 'Pour Some Sugar On Me' with the '6th Leppard' Robert John 'Mutt' Lange singing all the vocals. He's got a could voice.