dj,
You have spend a lot of time and effort with your photography, in my opinion you should include some of that work in this painting. A portrait of you and your boxster, you know you'll be proud of it because it is real and not fabricated. I agree with jeph's reply "I mean, I love the Ferrari F430 and Volvo P1800... but I would take a painting of my 1994 Ford Probe over those."
Personally I like the the style similar to what Grizzly posted, there are many examples you can look at here:
http://www.allposters.com/-st/Transportation-Vintage-Art-Posters_c9036_.htm look for vintage art + transportation.
I am jealous for sure, can't wait to see the finished painting.