anything with leaf springs all 4 corners is easy and fairly cheap to lift.
i'd go shackle flips in rear and lift springs up front.
if just for show, go with lift springs in the rear. if hauling weight, shackle flips are the way to go. bolt on in a couple hrs and re-use your stock leaf packs- gvw and capability stays the same as stock. a set of 3" blocks will accomplish the same thing as flips, but no worries about axle wrap and flips will ride a little smoother than blocks.
you will need lift springs for the front. as their just simple bent leaves, i would go with a set of Skyjacker, Superlift, Tuff Country or similar springs- they been making lift springs for HD trucks longer than anyone else, and lift springs are'nt exactly rocket science anyways. the front weight always stays the same, unless you add a 500 lb bumper, so that's a non-issue.
be aware if using shackle flips, they will push your axle ahead slightly, some people don't care, some use zero-rate springs to re-center the axle. i have bushwacker cut out fender flares so i was able to center mine using them.
no steering gear is really needed for 3", but an upgraded trac bar would be a big plus. pinion angle should be ok to with a long wheelbase, if not some shims can get your angles back quickly. brake lines should have plenty of slack for 3", if not some hose relocater brackets are your friend.
this is about the cheapest way to lift that will work and last, while being totally safe. as your truck is a heavyweight, i would just throw some good nitrogen shocks on it, who cares what brand, there all pretty much the same except for the stickers on them. ya not as fancy as reservoir shocks, but wit the weight of the Excursion they will give a good ride and long life and are much more AFFORDABLE. reservoir shocks are fine if you like blasting threw the bush at 80 mph....
i have the same style of lift on my truck, flips and springs- almost 20 yrs with zero probs, and i haul a truck camper and pull a quad trailer. my truck also weighs 8000 lbs empty too. size and weight don't really need to factor into the equation
