Unless you can defeat the laws of gravity, a level drain will not work. A pressure assist toilet uses the house water pressure to build up pressure in a tank that is in the toilet's tank. It's purpose is to blast the crap out of the toilet into the drain. The drain is NOT pressurized. A pressure assisted toilet is a gimmick that some manufacturers use to make a poorly designed toilet flush. They make an explosive sound when flushing, tend to shred the paper in the bowl which then remains in the bowl. Toto does not make a pressure assisted toilet because their toilets are designed to function without trickery. That point aside, you have to have a 1/4" per foot fall. I do not know enough about the macerating toilets to comment.