xB Gen 1 vs Yaris . . .

[woof]

I was pretty happy with my xB until I looked down and noticed I had 50K miles in just 24 months. Well, I like the styling of the Yaris and saddled up with one. Both cars are five speeds and the first thing I noticed is that the Yaris' mission in life is MPG and nothing else. Not only did my xB handle 100% better, it felt much quicker.

This all comes down to final drive ratio. How feasible is it to break open the trans axle to put in a lower overall ratio gear? As I recall, the the xB was about 300 pounds heavier but still seemed to move out more quickly than my Yaris and this had to be the main difference since the drive trains are identical.

Any ideas?