[masraum]

OK, the red arrows point to where I feel the leaks. I've got air that comes out of the vent pipe (we had the pipe capped a long time ago, and when capped, we heard gurgling noises coming from one of the upstairs bathtub drains. Uncapping the vent stopped the noise), some comes from where the insulated drain pipe comes out of the drain pan, and a ton can be felt when I stick my hand under the unit (can't tell exactly where the air is coming from, just feel it. sealing under is more of a pain so he did a crappy job?).

So, what is this "taping" of which you speak? I don't see any tape. My unit seems to be internally insulated sheet metal boxes that are screwed together and then gooped. I don't see any tape anywhere.