Just remember that the MI is not a free float . Many people including myself have taken free float forends from Ar-15's and made simple adapters to fit the Ar-180. Armedsask took it further by using a Predator system from POF .
One of these days I am going to get a Lightweight Forearm from Yankee Hill .
When using an adapted forend, the way you clean the gas system is different than with the factory handguard. You take the front sight off and pull the whole gas system forward and off. To prepare the sights for this, have the ears of the front sight aligned with the ears of the rear sight so upon re-installation of the front sight with the gas system you have a consistant system. A good way is to set the rifle upside down on a smooth, flat counter-top and tighten the front sight base. I hope this helps, If you have any questions about the adapter send me an email and I will help as I can.
Josh