clunking noise can be several things as Rev said. by bouncy you mean is continues to bounce after hitting the bump, that is shocks, if its a stiff bounce, then the torsion bars are cranked a little to begin with. if you are turning into a curb and your wheel is turned all the way you are on you steering stops and that can make a clunk/squeal noise. just lube the steering stops because the plastic pieces are gone.
be sure when you have it jacked up to check all of your steering components, suspension components, and driveline components on the front end.
as far as a lift kit, suspension - kits are out there and its about 2-3" of lift,
www.4x4parts.com but you can do what is called a PML (poor mans lift) by cranking up the torsion bars and adding a shackle to the rear this will be around 1-1/2", body lifts are inexpensive but IMO it shows the complete frame and I'm not a big fan of it. you can get a 3" SL and 3" BL and fit 33s without any rubbing (I'm told). I had Calmini SL and had 32s on factory lego rims and rubbed the torsion rod support on the frame at full turns. my friend has the kit now and as 33s and with some minor trimming to the rear of the front fender only rubs where I rubbed now.
regardless, I would 1st thing get an idler arm bracket, this is the weakest point in the steering and bends very easily. there are quite a few offroad sites on the web for nissans, 2 are based out of CO. search these sites and you could possibly pick up a SL cheap. people on these sights like to SAS their trucks for better performance offroad. here are a few...
www.roninwheelers.com
www.nissan4wheelers.com
www.4x4parts.com
www.ruggedrocksoffroad.com
www.nissanoffroad.net
www.nissanwheelers.com
www.nissantrailriders.com