For the reducer/adapter from 2.75" to 3", you can get a silicone fitting for that. They're pricy though, and you'll need clamps.
Something like this:
K&N makes a nice cone filter with a 3" diameter. I have one on the Focus and it sure does suck (in a good way). And its easy to clean.
Something along these lines:
I have just about the same size one on the Focus, just its a bit shorter from the looks of that picture (mine is about 8" long)
Not sure how much space you have to deal with, but you may need a shorter length filter.
And if you can't get it out of the engine bay, you can probably fabricate something like this:
The MAF.. no idea :(
hope that helps you out a bit!