I'll take your last question first. Yes, assuming you study effectively and sufficiently of course, either option should work for most people. (You say "a great score" - I'm interpreting that to mean somewhere from 660 to 710, which is the most common goal score range that I hear from people. If you want a 750+, then you'll probably need more than the "regular" program - but you'd still need to get through the regular stuff to lift yourself to 700 or so before you could push even further.)
The one wild card is the one big difference between the two programs: how much you would benefit from having direct access to an instructor.
The regular and self-study programs include all of the same books and online resources. One of the self-study programs includes access to apes of the classes; the other doesn't.
Obviously, anybody will benefit from being able to ask questions during a class - that's why it costs more to attend a class with live instructors, rather than have access to a tape. Do you need that benefit? I don't know - it really depends on you.
As a general rule, I'll say that having access to someone who listens to your specific question and can address it and even ask you further questions to find the best way to help you - well, that's really valuable in general. You'll have to decide whether you think it's beneficial enough that you're willing to pay extra for it. :)
I'd recommend sitting in on a first class for free (we offer this for any of our regular classes). See what you think, and try to imagine what things would be the same and what things would be different if you were watching a tape and couldn't actually ask when you had a question.
And of course feel free to ask if you have more questions. The one thing I'll recommend - as you have probably figured out by now, the Ask an Instructor section of the forums isn't the place to go to get quick answers to questions. If you've got "buying-decision" type questions and want to talk to somebody, call our office (800.576.GMAT) or send an email (
studentservices@manhattangmat.com) and somebody will be happy to answer any questions you have.