One more thing, do you guys think a 2008 MDX would have the same brake booster as the RDX? Just a question
Before I order online I am going to my local junkyard to see If I can find my car (or an MDX if its possible) so that Way I can get it for wayyyyyy cheaper.
I looked at both on Rock Auto and the part number isn’t the same for the MDX as the RDX, so my guess is probably not
The OP spent money for sub woofers but is trying to be cheap on something as important as brakes . Apparently they are not in the US so we have no idea how available parts are .
I still say when non - professionals are working on brakes new parts should be used from a known source. Not some firm on Ebay that might not even exist next week.
Got to have your priorities straight 
Yeah but a used working one is better than mine with a hole that is hissing.