Plenty of different options for air cleaners available, a lot of guys run the "sock" type air cleaners. I use these but the lid runs a little too close to the ram tubes - need to swap them out for shorter tubes but never got around to it.
Never do this. Some people do - but the power loss from removing the trumpets is massive. The air cleaner base plate goes on first then use the trumpets and retaining washers to hold the plate in place.