My suggestions:
1. Get into the back seat. Ask a friend to drive. Call him Smithers for the duration of the review. Doesn't matter what his actual name is. Insist that he wear a waistcoat. The ideal Smithers is tall and thin and can look askance upon everyone upto the Queen. Type up your review from the back seat.
2. Do this while parked - the famed Clarkson tea test. You will need: a thermos filled with hot tea, tea biscuits (which are a wee bit like really thin cookies, but without the calories and the sadness), someone to pour you the tea / someone you pour the tea for. Either works. The test is to see whether a little spot of tea in the rear seat of your plutocrat-barge will overwhelm the A/C and fog up the windows. Remember, the gold standard is that renowned people-mover, the VW Phaeton.
3. The third test is the long drive. Smithers will drive you across atleast 150 miles of an Interstate of your choice. As an aside, we should rename Interstates to FreedomRoads ('Murica!) Make sure you carry an accurate thermometer, or maybe five. The cabin temperature should not vary by more than 1 degree Celsius from the target setting through the duration of the journey.
4. Is there that flap which opens the passenger front seatback and turns it into a footrest? Use it!
5. How do people on the road treat you? This is the time to make astute observations and pithy comments about the plebes in their econoboxes and the deluded riches in their autobahnstormers.
Write the whole thing up. Thank me.