Limitations for a 2008 Pathfinder w/ V8

Time for an update on my towing experience. Traded my 2006 Roo 21RS for a 2014 Roo 25RS and absolutely love the space increase / amenities etc., great camper! Now for the painful part, the info. about payload issues turned out to be correct. The Pathy V8 had plenty of torque to tow the heavier rig, (which by the way has a very underestimated dry weight, all the internet info shows it as 4900lbs, but the sticker on the front corner says 5300lbs) get it moving just fine and get it over hills with moderately more effort than the 21 the issue turned out sure enough to be severe sway. After a couple of trips and fully "moving in" with all our stuff it was clear the setup was unmanageable and dangerous on the hiway at any speed over 40-45mph and on any secondary road over 55mph. We even bought a better two bar WD / anti sway hitch and the trailer sat level but the Pathy was nose high. Basically with passengers, tongue weight and a full tank of gas we were sitting on top of the payload limit with no gear in the car at all and close enough to the tow limit to really feel it. So it was either get a better tow vehicle or go 45mph every time we camped and that's not realistic or safe. Thankfully it was time to trade my '02 Frontier Crew cab anyway and I bit the bullet and got a '11 Ram 2500 Mega Cab with the Hemi. Not a diesel fan and didn't need it for this rig. In fact it tows it so well I feel confident about going up in trailer size if the need ever arose. I chose the 2500 over the 1500 because even though the tow ratings are similar the payload is much higher and we like to haul a lot of stuff. It may be a bit of overkill but after two trailers and two vehicle swaps to support the camping process over the last year and a half I was ready to put this issue to bed once and for all. Thanks to everyone who contributed, it was all very helpful. At the end of the day my general rule of thumb from all this hands on experience is stay roughly 2000lbs below your vehicles stated tow limit and it will be a manageable, stress free ride. A big truck may give a bit more breathing room than that but the closer you get to the limit on any given vehicle the more you know it.