Re: What did you do to your Crossfire today?
Just observing that you are oversimplifying to just consider gear ratios and speeds. but even from your chart you can see the XF is not a high winding engine.
When designing a gearbox for a racng car you have to consider a lot of things but the car weight and torque curve are the most critical.
You mention the Miata. Torque peaks at 5000 rpm and it has VVT. It can use high winding gears particularly with about 50% less IHP.
OTOH the Crossie is thoroughly last century SOHC, no VVT and a torque peak at 3000, 2000 rpm lower than the Miata. This is an engine that needs long gears and a five speed with granny (5th is 1:1) is not the best choice. I am sure it was made for cost and inventory but not engineering reasons.
That said it is what we have and a $2000 gearbox or $1000 rear axle for 600 rpm less on the turnpike is not cost justifyable for a toy car. But is what the XF needs.
And on the gripping hand it is a good car for a learner since is almost impossible to stall in first.