These changes are pretty significant but I really have to agree with all of these. Especially 3A (challenge of downs by contact) and 3B (No penalty when an offensive lineman touches the ball first)(David Carr probably could have benefited from this rule somewhat as well as QBs who have a sidearm delivery). I do NOT like unchallengable plays one iota and this just changes a lot. With the new quality of Instant replay interwined with the new 60 second rule. There should be NOT BE A SINGLE PLAY that is unchallengable. Of course, I was happy with the 90 second rule but it shouldn't make all that much of a difference when you factor in the higher quality being implemented. I really like what the NFL has done here. To quote a buddy of mine, "Fine-tuning the greatest sport in the galaxy." Let's hear your thoughts on these rule changes, fellows!