Op... i havent towed with the 4runmer yet, hut a biddy has. He said it did fine, he was using my open steel trailer with his m3 on it. Probably together were about 4500lbs. Plus the 4runner had tools and supporting gear.
I had a 2013 Tundra that I towed with. Had the 5.7L. It was abosuletly boss at towing. Accelerated like a cheetah with its ass on fire. Fully loaded I towed my M3 which was about 4700lbs. Plus supporting gear and two other cars supporting gear. So all told probably 12klbs running dow the road. It did everything Inasked it to do, except get good MPG. But i bought it solely for towing.
My daily driver died last year... motor got sick. So ihad to daily the Tundra. I have to say the Tundra as a daily was horrible. Shit MPG, 13 was my best, wide and hard to park. It got old quick. My wife did drive it and even shoe horned it in parking decks on the top floor, away from other cars, double humping a spot.
I say get the 4runmer, but get an aliminum trailer to try to get some tow capacity back. Open trailer will be even lighter like a trailex. Or a full deck like alumna or others.
Just take it easy on the tow.