I had an RX300 until quite recently, had a hitch receiver put on and pulled an enclosed 8' trailer full of 800 lbs. of art festival items, or my BMW 650 motorcycle up and down CO Rockies. I've never had an issue with it. My mechanic did talk me out of a motorcycle carrier on the hitch receiver - he says unless the bike is really light (Trials, 125cc, etc), most vehicles aren't built to carry that much weight on the back end - stresses out the suspension. A trailer's weight is partially supported by its tires. FWIW
BTW, I'm looking for a light-colored RX300 w/ less than 150K miles if anyone knows of one for sale anywhere in CO. I had an encounter with a deer which did not end well for my RX.