when I was there a few weeks ago, I did it on my own and listened in on other tours where I could....cheap I know but it allowed me to go at my own pace and see all I wanted to see
Indeed, very cheap, considering how little the tour guides actually earn ... and NO, going with a tour guide does not mean that you cannot go at your own pace and don't see all you wanted to see. Quite the opposite! Having a guide will allow you to actually FIND what you want to see in this huge maze. And after your 2 hour tour is done you can stay as long as you like to see anything else you desire.