2004 29B, hitch was up-rated that year to 5000 pounds but still 350 limit on tongue weight.
I now flat tow a manual transmission Honda Fit (about 2500 pounds).
Before that flat towed a manual transmission 2001 Ford Ranger (regular cab Edge trim, about 3200 pounds). The Ranger was heavy enough to push around this RV on very tight curves (e.g. marked 15-20 mph) if I tried to take them close to the marked speeds. 29B model has a very long rear overhang in proportion to the wheelbase, you have to tow gently.
Your only realistic option for towing that particular car is a dolly, unless you can upgrade the hitch. Putting a 3100 pound car on a trailer will exceed ratings for tongue weight and leverage weight off the front axle, and the 29B is already too light on the front end with normal loading.
Tom Test
Itasca Spirit 29B