Where's a good source for ordering an upper with a micro gas block already installed?

Thinking about getting a 14.5 or 16 inch upper (prefer something like BCM/LMT/CMMG), with a micro gas block so I can add some long free float rails/handguards on them myslef.....

I think some places ship the upper with a front sight base and the gas block separately and make you do it yourself....

The micro gas block is CMMG's baby, you should give them a call.

just go to the Yankee hill Machine website and order the Specter Gas Block, I installed one on my rifle and I was able to install my free float rail over it.  The best part was not having to drill into the barrel, it is just a two piece design that is held in place by 4 hex bolts. Just click on the link.

Spector gas block

I don't have a picture of my rifle right since I am away from home or I would show you.

So installing the low profile gass block yourself is the best option?

Are all low profile gas blocks created equal or is the price diff b/w them mostly in the name brand?