33's are not that hard to get under a durango. I have a 99, and all you have to do is get a set of indexed torsion keys (find em on ebay all the time) that will allow you to get about 3 inches out of the front torsion bars and then get a set of longer shackles and an add aleaf in the rear. Although the biggest problem with the 33's is the width, so you will have to replace your wheels with something more offset, and I highly recommend sticking with an 8 inch wide wheel to keep the tire from killing your inner fenders. A lot of durango owners just crank the stock torsion bars 2 inches do the rear shackle and put on 32's. You won't want to go any bigger than 32-33's though without addressing axles. The front axle is prone to pumkin failure with too much tire.
The 5.5 inch lift is made by tuff country, and has a bad name for bending brackets under heavy wheeling, but I have no personal experience with it. Just FYI.
As far as durnagos go though I love mine. Hands down take it over a burban. I average about 16 mpg overal and get 17 on straight highway. Not that it's awsome but considering a V8 suv I'm satisfied. My brother in law can't seem to get over 15 in his burban even on the freeway. And anyone who has ever tried to wheel a burban will tell you you need at least 35's just to keep the bumpers from dragging.
However, my durango is just biding it's time though till the used market comes down on the new 4 door wrangler unlimiteds. Since Jeeps are where the real fun are of course.
If you have any questions I can awnser on durangos let me know I've put my time in. Or check out the durango forum at dodgetalk.com there is tons of info on them over there.
