Are these versions without guitar & vocals made using the guitar hero stems? If so, I did the same for myself so I can play my guitar and sing along with Queen backing me in the comfort of my own living room. Great fun!
Of course, it's nice we have the stems and they are endlessly fascinating - but I think they are the worst thing to happen to the 'bootleg' pool for a long time, watering it down.
PS I love the brighton rock stems, sounds like they're having a whale of a time :o)