Anybody running 276 gears?

If you truly drive the car "a lot," overdrive is really the way to go.

I think you have to ask yourself: How much would it cost you to re-gear the diff? And how much would it cost to have an overdrive transmission installed? And what's the difference between those two numbers.

You will never make up the cost difference in fuel (I did the math, for me it would take about 85,000 km), but the driving experience is night and day with OD. The experience becomes more important when you're driving the car all the time, especially if you're cruising highways and country roads.