Readers ask some odd questions. One recent e-mail was from a guy who wondered if I could recommend him to management as my successor if I were planning to get out of Dodge.

Another came from a fellow who thought I might be interested in a Mazda Miata with 147,000 miles on it.

But most of the questions I get aren't odd. They're sensible inquiries, some of which recur with frequency. I thought it might be of interest if I answered a few FAQs.

Question: I'm debating whether to buy a new car or a late-model used one. What do you think?

Answer: I lean toward the late-model used vehicle, preferably a low-mileage ride coming off a three-year lease. That way, you let someone else take that brutal initial depreciation and save a good buck in the process.

Alternatively, you might spend the same amount you could afford to spend on a new car and get a more upscale used one.

The used car makes more sense than it once did because modern vehicles are so much more durable than their ancestors were. And that enhanced longevity figures in those extended warranties dealers put on their certified used cars.

Q: My new car will run on regular gas, but would I get better power or mileage if I put mid-grade or premium in it?

A: No, you'd just be wasting your money.

Q: Would you recommend using synthetic oil?

A: It depends on how long you plan to keep your vehicle. If you drive a car only two or three years, the synthetic's superior lubrication isn't going to justify its additional cost for you. But if you keep a vehicle for quite a while, it could pay off. (I use synthetic in my car, and that engine is still running like a Rolex at 168,000 miles.)

Q: What do you think of diesels?

A: The modern turbo-diesel is intrinsically superior to a gas engine. It is much more fuel-efficient, lasts longer, and develops a lot more torque, which is real-world power.

The latest generation of pleasure-car diesels, particularly those built by the Germans, are also so much cleaner and quieter than their forebears.

Whether they are a good investment depends on how long you keep them. Obviously, it takes a while for the greater fuel economy to offset the multi-thousand-dollar premium for the diesel engine - and the higher cost of diesel fuel.

Q: My front-drive car is so good in snow. Why are there still a number of rear-drive cars being built?

A: Maybe because they're a better idea from a driving-dynamics standpoint. That's why sports cars like the Porsche and the Corvette are rear-drive, as are most upmarket sedans.

The front-drive car offers no performance benefits except for its traction in snow, which decreases as the grade gets steeper and the drivetrain weight shifts back off the front-drive wheels.

Indeed, the shift to front-drive was purely a packaging solution - by using a front-drive layout in which the engine is mounted transversely, designers were able to move the firewall forward and increase cabin space in America's shrinking automobiles.

By mounting the entire drivetrain at the front of the car, you wind up with a front-end-heavy vehicle with much poorer fore-to-aft weight balance than a rear-driver. Understeer in cornering maneuvers is more pronounced.

In short, a front-driver asks the front wheels to do all the steering and propulsion and most of the braking, and that's a lot of weight to place on those narrow shoulders.