2009 Mazda6 starting at $19,220

[Tone]

I would guess that the Mazda5 doesn't need to rev 3100 rpm to maintani 75 mph -- the engine only needs a small fraction of its full power to cruise at that speed. Taller gearing (say running 2500 rpm at 75 mph) would require more throttle to maintain the same speed, though. This is actually good for fuel economy -- it reduces pumping losses, so the engine is actually more efficient.

The downside is that acceleration from this speed would be far more sluggish and might require a downshift for passing or steep hills.

I too sometimes wish for a taller sixth gear in my Protege, even if it did mean the occasional downshift!