Higher numbers = lower gear ratio

The only benefit would be a little quicker launch off the line. I don't know anout the 6 speed but the 5 speed has a pretty low first gear already.

Now you you really mean a Higher gear ratio (lower number), it would be a little sluggish off the line but you would get a little better fuel mileage cruising on the interstate. However your city fuel mileage would suffer.

It all depends on what you're looking to accomplish and what your personal driving habbits are.

In any case... Do whatever it takes to taylor the car for yourself.