Usually my custom luxo-barge-mutt car. I commissioned a custom car awhile back and by some miracle it actually got built. The factory managed to shoehorn 3 different platform's parts into one car. 44 MPG, no hybrid garbage. Insulated from the outside world on the inside. You don't even hear a fire truck behind you. Everything Bosch Mobility had to offer at the time was installed, so it is capable of self-driving, but my state doesn't allow it. It still does most of its on its own, which makes long 4+ hour drives enjoyable and relaxing. Separate fridge and oven as well for those long drives. It's nice to be on a business trip, get into the hotel late, and have a hot meal ready.
Then there's the time machine:
At the extreme, this baby can cut a 6 hour drive down to 60 minutes. For more mundane trips it cuts 3 hour trips down to 1 hour. Very susceptible to weather, which requires some planning and flexibility, but when everything works out, it truly is a time machine. Being able to get to a client's office in 1-2 hours instead of 3-8 hours is a game changer and saves money as well. Still slow enough that I don't have to worry about the speed limits and I don't have to worry about traffic in the conventional sense.
There's also a twisted irony -- I'm federally mandated to burn LEADED gas in the plane. This same government also prohibited me from equipping my car with a diesel-electric powertrain which would have given the car ~85 MPG (real MPG, not eMPG garbage), insisting the "approved" 25MPG powertrain was more environmentally-friendly. Fortunately I was able to push that powertrain up to the 44MPG with some modifications. Not compliant, but to me 44 MPG is better than 25 MPG for the Earth and my wallet.