I have towed more than 100,000 miles (work and play) with my '08 Highlander. Wheelbase is about 107" IIRC. 5000/500 tow limit. My cargo trailer was 17' long and about 3800 lb loaded, 410 on the hitch. The TT (until this past summer) was 16' long, 2700 lb loaded with 350 to 390 on the hitch, depending. It handled fine at 60 and 65 mph highway driving. Never any sway, and no scary moments. I did finally get an Andersen No-Sway hitch for the last year just because my wife complained about the jiggling caused by the trailer tongue, and the Andersen smoothed out about 80% of the motions. But I never felt like I needed it for safety.
I can't imagine you needing WD with your Lexus as long as you load the TT properly (10-15% of weight on hitch) and avoid driving 75 mph.
