Especially with a lower-profile sedan like yours there's a considerable difference between towing a popup and a stand-up trailer, the most important of which is the huge increase in wind resistance you'll encounter with such a change. That aside:
None of the "upgrades" you describe will increase mfr's limits for the car. One can probably install a 4,000 lb receiver on a Minicooper, but the weakest link will still govern the real world limits.
Towing limit for your car is expressed
at this link as 1500 pounds, and even that's assuming upgrades to engine/drive train.
But since you're already exceeding that by over a hundred percent, I say "what the heck"? Keep pilin' it on until the car quits!