DO NOT PUT 5 QUARTS!!!! Overfilling will do several bad things.
1. Zetecs need an oil temperature of around 220-250 degrees for proper lubrication and viscosity. Overfilling the oil (or installing an oil cooler) will cause the heat to be spread out more and you will have low oil temperatures during operation. This causes severe cylinder wall wear, and prevents moisture from burning off in your crankcase. Other than severe on-track racing use, Zetecs do not need any oil coolers or additional capacity. If you overfill, use a bigger filter, oil cooler, etc. you are wearing out your engine for no reason. Some cars can benefit from this, but ours does not.
2. Overfilling can cause rotating parts like the counterweights on the crankshaft to come into contact with the oil which aerates it and whips it into a froth. This is difficult for the oil pump to pump, resulting in low oil pressure which will cause engine failure.
A quart low is always better than a quart over, if you're ever in doubt.
I pour 4 quarts in, start the engine, run it for 15 seconds, and then turn it off, wait 30 seconds, and check it. I then add to bring it to the full mark and not over.
My opinion on oil is either go with full synthetic or the cheapest conventional oil you can find. As far as dino oils go, they are all the same. I have used no-name brand 5w30 for over 100k miles on my zetec and I expect to get another 200k out of it. We can argue about this till everyone is blue in the face but my two cents is this: buy the cheapest API-SL/SM oil you can find and save your money for something that matters.