Should I consider the accurizing wedge then if there is chatter between my lower and upper? I have not fit them yet bit will check on that when I get them. I did some reading, some say it was difficult if not impossible to get a good fit when using it (couldn't close action) Tips?

you may need to trim/sand it down but it really shouldn't be too hard.  I'd suggest putting your rifle together and seeing if it even needs the wedge.  Some people don't give a crap about a slight rattle or may not even notice it.  If you do, stick it in and slowly shave it down until you get the fit you want.  It's all trial and error and it is pretty easy to do, buy a few (they are cheap) just in case you screw up the first one although if you go slowly, I doubt you will have very much of a problem. 

Redesigned or not, it's stuff like this that would always be on my mind...

yes but I'm sure we have all seen these pictures before and again, these are 2 out of how many thousands of polymer lowers made and used and who is to say a these failures are not due to bad ammo.  Doesn't really matter as the OP has already bought his lower already but I've seen even forged lowers have problems/cracks...  As for glock making lowers, I've seen quite a bit of glocks blow up as well but usually its due to ammo and not the polymer guns being the problem.

http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%2055,%20Receiver%20Tightness.pdf

enough said

http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%2055,%20Receiver%20Tightness.pdf

enough said

yes and no, yes in that I personally do not believe looseness affects accuracy as the relationship between the scope and barrel has nothing to do with the fitment between the upper and lower receiver and that the bullet would exit long before it had an effect on the upper movement and the lowers but no in that the article you submitted is not a double blinded study with any type of peer review so it is basically worthless as if I were to have written it.  Does not matter if it came from a reputable company, it holds no water with any scientific community. 

Either way, I find one of the easiest ways to remove rattle for more confidence in your weapon would be the little wedge.  They cost like 2-3 bucks and work to remove the rattle.

yes and no, yes in that I personally do not believe looseness affects accuracy as the relationship between the scope and barrel has nothing to do with the fitment between the upper and lower receiver and that the bullet would exit long before it had an effect on the upper movement and the lowers but no in that the article you submitted is not a double blinded study with any type of peer review so it is basically worthless as if I were to have written it.  Does not matter if it came from a reputable company, it holds no water with any scientific community. 

Either way, I find one of the easiest ways to remove rattle for more confidence in your weapon would be the little wedge.  They cost like 2-3 bucks and work to remove the rattle.

I did not refer to this article as a peer reviewed article and I can't find the results from the Rodman Labs. We can argue on the forums to no avail.  The AMU is a well established unit that has very reputable armorers and shooters from all disciplines.
You're more than welcome to prove your point .

I have not seen any measureable differences in fit and accuracy for ARs. Confidence is a major factor in winning matches. If a tight fit or a rubber wedge helps with building that confidence, then go for it. I have been in "as issued" service rifle matches that listed such wedges as illegal for these competitions. The top 5 shooters from each relay had to have their rifles inspected for modification at the completion of the course of fire. On a side note,  "Light enhancing"  glasses (amber or vermillion) were also on the banned list for these matches.

The bottom line is that you should do it if it makes a difference to you.