Man, I wish you all the luck in the world with getting together a group like the old Chicago. I'd buy the album! IMHO, the first five Chicago albums are great. (That would be through the "wood cover" album.) The only caveat would be that their Live In Japan album is a bit more loose than Carenegie Hall collection, and much closer to what the band sounded like back in the days of Terry Kath, so I would add that disc to my list of great Chicago discs too. Starting with the 6th album, they started to lose me.
You can live in staunch denile and mark me as your enemy, but I'm just a voice among the throng who want a brighter destiny, and say with me, "We are the New America!" -Greg Graffin