I had a 2003 Nissan 350z (blue, 6speed manual) and a 2002 Audi A4 3.0 Quattro when my Model S arrived. I loved the Z, and it was my first brand new car I ever purchased, and did it all on my own. Drove it for ~95,000 miles over 11 years, dragged raced it and auto-crossed it. And within two days of having my Tesla Model S P85+ ... I knew I'd never drive the Z again. (It was bitter-sweet realization.) So two days ... but logistically took about month before I got around to get it sold.
I've kept the Audi, because I'm a snowboarder, and head up to Tahoe - which is the whole reason I bought that car (and its got like a brand new set of snow tires on it). When the MS was in for the 12.5k service (it got a new drive motor and master charger ... so it was at the service center for 2.5 days) - I drove the Audi ... which is a great car ... but felt like a tiny go-cart I was cramped into. Was also the first time I touch a gas pump in 5+ months.
With the P85D ... only being about $3-4k more than I spent on the P85+ ... it is really tempting to trade up, and go a solo, all electric garage. The Audi cost less per year to keep (insurance+registration) than to rent a car for the weekend (especially AWD) - and it's a little beat up ... probably only worth $3-4k ... so for right now, will be holding steady with the P85+ and the A4.
I live in an area and have a lifestyle that works very well for an all electric (at least an all Tesla) garage. Other than loaning Audi out to a friend for a few weeks, and the 2.5 days I drove it while the Model S was in for service ... the Audi probably won't get driven again until there are the lifts are running up at Heavenly.
7 months, 15,000+ miles ... 4 round trips from SF (RWC) <-> LA (once to SD, and then up to Sac and back SF/RWC) ... no issues, never ran out of charge. No regrets. (Well, other than not being able to place an order for a P85D ... right now.)