You probably won't find the better Bushmaster (or any other brand) configurations as new, complete rifles.  That's because manufacturers put their cheapest barrels (which means heavy barrels, or HBARs) on their complete guns, so that the gun will have the lowest price possible, and look good against the competition.

But the best (for most uses) configurations use lightweight barrels.  And because these have to spend more time on the lathe to get turned down from barrel blanks, they cost a bit more.

So, I always recommend buying a complete lower half from your dealer, then ORDERING an upper in your favorite, lightweight configuration, directly from Bushmaster.  This will take longer to put a complete rifle in your hands, and may end up costing slightly more than buying a complete gun, but it will be cheaper than having to buy a new barrel to replace an overly-heavy HBAR.  So why not get exactly what you want?

Bushmaster recently began making a lightweight Dissipator (the "M4 Dissipator), which you might like.  Plenty of other configurations as well.

Decide if you want a plain muzzle, or if you want a muzzle brake (you can't legally install a flash suppressor on a post-ban rifle).  Kurt's Kustom Firearms and others make muzzle brakes that look very much like an A2 flash suppressor, but are post-ban legal when permanently installed.  If you want one, it's better to order your barrel threaded from the factory, but with the bayo lug removed (also a no-no on a post-ban gun).  Then ship the upper off to have the brake permanently installed.  See Kurt's forum in the Industry Forums for pics.

-Troy