ok man get to answer the first question as im sure you know hot air rises so the colder air is down lower so your intake i would cut fairly low down now the dissadvantage to that is dust and stuff from the ground can get sucked in now with sealed shields i dont think that will make much difference then i would cut the one for your outake higher up dont worry about keeping things level man its gonna cause you more headaches than anything just make sure to use a bit longer piece of ducting than is needed just to be safe i hope this helped a bit