I'm surprised no one has posted this yet. Here's an awesome description of every little detail about Barr Trail from top to bottom written by none other than Matt Carpenter, the course record holder. I studied it a ton before my first time up and I'm glad I was a little more prepared.
http://skyrunner.com/ppcourse.htm
This second link is a pace calculator. My first time running to the top of Barr Trail was after living in Colorado Springs for several months, so I was also acclimated, just like you. I predicted my time would be similar to my current marathon fitness level at the time, but I ended up being about 9 minutes slower.
http://skyrunner.com/pace.htm
I would highly recommend using the calculator above and writing your splits on something the size of a business card so it fits nicely in your pocket/backpack. Just make sure to cover it with a bunch of tape to keep the moisture from destroying the paper when you sweat. I've done this several times as my fitness has improved and it's helped me stay on pace very accurately without blowing up.
As a lot of people have already mentioned, those last 3 miles above the tree line are going to be a death march no matter how fit you are. Save some energy for this section because you'll pay the price if you don't. A couple others said that they regretted pushing the pace during the one flat-ish section of the trail that gives you a short break from climbing around mile 4-5. It may look like it's your only time to pass people since the trail is narrow in most places, but you'll be glad you held back when you start passing those who are struggling during the last few miles.
Don't forget to keep eating and staying hydrated, especially above Barr Camp (roughly halfway to the top). Also, I'm sure you were here for the crazy storms last week. I saw some pictures of washouts on Barr Trail from all the runoff, so the trail may not be in the best condition right now. That's just one more reason to wear good trail shoes in case traction is an issue.