Hi - I just put garageband on my iPad (first experience with garageband) and it blew me away. I'm now considering buying a mac because my Korg X3 is well past its prime. I'm totally new to garageband. Some quick questions: 1) How many tracks can you record in a song? 8? 16? 2) Any limits on polyphony? 3) I can't play guitar at all. If I also buy a USB keyboard like the m-audio model, can that be used to play drums, guitar etc? 4) I'm not made of money - does a base entry macbook pro or imac have enough horsepower to run garageband well? Any suggestions on which route to go there? Thanks in advance!