How hard is it to put a windshield and the glass for the front passenger door in an EA81 4 door sedan?

Not too difficult (everything is easy when you know it). Not to be a smart alec, but if you aren't experienced with glass installation, spend the extra $50.00 and have it done professionally. The cost of the glass itself is worth it, not to mention the chance of installing one that will leak on you. The door glass is also easy, but you could beat your knockles to death if you haven't spent much time inside a door panel. Be careful not to overtighten things and to roll the window up and down several times to ensure that the glass is exactly where it is supposed to be before sealing things up. Good luck.