BY CHRIS TALNOTTASST. ARTS EDITORFew bands have come as far as the Goo Goo Dolls have in the past five years. The Buffalo-based trio, which plays at the Downunder Saturday, has changed their sound and their lifestyle completely. According to George (the Goo Goo Dolls don't use their last names), the band's drummer, that change has given them a whole new look at life. "I think every day I live I'm starting to enjoy it more." George said in a phone interview from New York City where the band was taking a break between shows. "It gets easier. I mean we've come from when we started and all the cra