I started towing with the LR3 at 105K and we're at about 130k now and no real issues...its also my DD - all maintenance is done but I can tell I need to change the tranny fluid here before the summer pulling season. We go up and down the coast which includes going up the grape vine (I5) grade which is very long up and down and other then just taking it slow and steady with the big rigs here it pulls just fine pretty much everywhere else. Sometimes if we go to a lake or camp ground that's really steep (and we've been to a couple) I'll have to take is super slow but we always make it...haven't needed 4-low yet

- I also try to increase the fluid changes by 2x the recommended intervals (or once every year for front and rear gears/transfercase) and do the transfluid every 50k or whenever I feel that it's not shifting really smoothly.
On our last trip I did notice that the front end was pretty well worked over - some very steep grades so I'm swapping out both lower control arms and tie rods....brakes are ok as I just did them but I highly recommend going with a better pad...never liked the stock ones much. Something with a little more bite works well. I pull a large popup but also have 3 kids and all of our junk so the lr3 is at max weight (trailer is about 5500 dry but with all the crap) and the roofrack and interior is pretty well stuffed.
The low profile of the popup compared to a full hard sided trailer makes little difference for the anti sway hitch - but I still use the bars as we get a lot of gusty cross winds on the 5 and it just gives you that little extra help...haven't noticed the air pump coming on or off any more or less with or without the bars and as an engineer I can't see a reason why you wouldn't want to run them if you have them. We're planning on switching to a hard at the end of the year and as long as the loading and tire pressures are all good all the way around I don't think we'll have any isssues. I'm also running a rod lift and 32s - I do notice that the lr3 gears (especially 2nd gear when going up and down a steep hill) is a little off but that's my fault for changing the overall diameter and it's really only in that 1500-2000 rpm range in 2nd so usually it's not much of an issue... I'm also running the p3 controller and highly recommend it. just my experience but don't see why any properly cared for rig can't pull towing duties as well as its looked after..