[TurboVenom]

Neil,
I have 17 in. wheels but they're different sizes front and rear. If you need to carry a spare, you will probably need to use the same size tires all the way around. That kinda sux as big rear tires make the look of the car.
I don't carry a spare, but keep a cell phone charged all the time...

My car has power steering, power brakes and automatic. It's just lacking the radio. With the li'l six cylinder engine, I get 25 MPG on the highway, and around 13 MPG hot roddin'.

Fuel consumption has largely to do with cubic inches, more so than the weight of the vehicle. You need to maintain AF ratios for given displacement, so gas mileage won't vary too much away from the donor vehicle. The heat issue under the hood is perpetuated by the small oval cobra grille, and the fact that you tend to get weird air swirling around in the grille opening at certain speeds, causing lack of airflow across the radiator.

The grille opening is filled with this plastic mesh material that I got from McMaster Carr...real inexpensive. I also put guards on the rear fender bulges so stones don't eat the paint up too much. Those are adhesive backed and I purchased them from Everett-Morrison.