I have a Oly 20" A2 I picked up a few months ago, and I do enjoy it for what it is, however my biggest complaint is the trigger.  I've looked into a few triggers and decided that the jewell trigger is a bit much for what I want to spend.  Currently the trigger is single stage and approx 7-9 lb pull.  I'm looking for a nice two stage with a 2.5-3.5 lb break.  Any suggestions? Prices?  How hard is it to change out the trigger on an AR?  I did a RSA trigger on my SAR-1 in about 20 min start to finish, and it is as smooth as glass.

Easy, get a Rock River two stage. About $95 or so.

Changing triggers is easy with the AR. Just read and follow the directions that come with it.

Yep, I got 2 and used JP Enterprises reduced power trigger and hammer springs. Nice.