Rush's massive 'R40' box packs in plenty of rare and unreleased material -- and if you buy the 'Completist' version of the set, there's even more where that came from.

The expanded 'R40,' available through the band's Backstage Club as well as at Best Buy, adds a bonus disc to the box's 10-DVD (or six Blu-ray) length, and although the contents of the bonus disc differ depending on your chosen format, the end result still adds up to the same material. It's a little complicated, but fortunately, we were able to turn to Rush Is a Band for an explanation.

On DVD, the 'R40 Completist' bonus disc adds eight songs that weren't included on the original DVD release of 2005's 'R30' collection, plus the 'Anthem Castle Session' video and three more songs -- recorded at the Molson Amphitheatre in 1997 -- that were left off the standard 'R40' bonus disc. The Blu-ray version leaves off the eight 'R30' tracks, since they were already included on the 'R30' Blu-ray, but adds the bonus features from the 'R30' DVD deluxe edition -- which were not included on the Blu-ray editions of 'R30' or 'R40.'

That's a lot of Rs and numbers. What it all comes down to, according to Rush Is a Band's post, is this: "In short, if you already own the 'R30' Deluxe Edition DVD and the 2009 'R30' Blu-ray, then the only extra content that you are getting on the 'Completist' disc are the three additional Molson Amphitheatre songs."

While your brain processes all that information, you can watch the Best Buy-produced 'Completist' trailer above and try to figure out which version of 'R40' is the one most worth adding to your collection. Here's hoping 'R50' is only half as convoluted.

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