Now you'll never have to change the brakes again!
Will you continue your tradition of putting a boat tail on every car you've owned with the Mirage?
If I had a Mirage I would definitely get the UK-spec final drive and use it with the US-spec gears - IIRC the UK is the one with the taller final drive and the US has the shorter final drive, but a taller 5th gear? But that would probably be expensive, sooooo.
I probably wouldn't go with taller tires, because RE92s.
It would be interesting to see whether taller gearing + not as LRR tire or stock gearing + RE92s is best for FE.