TBH, You buy your Zed for whatever reason, so personally, I'm not too fussed about MPG, sometimes it's good, sometimes it's not, just the way it goes.
But at the end of the day........(caution NSFW)
All depends on the width of the wheel I guess, I had to remove the spare when transporting my 19" Volks, fronts on passenger seat and rears in the back
Look here for headlight adjustment, did mine this way and it's a lot better than when I first got the car
http://www.350z-tech.com/wiki/index.php?title=Headlight_Adjustment
While you're there taking bits apart, check the calipers for caked on brake dust residue, especially where the pad guides are.
When changing the rears on mine recently, I noticed it was quite hard to remove the pads.
Once I did have them out i gave the calipers a good inspection and clean up (used a steel punch for the proper caked on bits).
With the residue gone, the pads slid in like butter.
This is where it becomes interesting......
Send wax pot to US to be refilled via insured method, It gets refilled and sent back to UK. Great so far...... Gets stuck in customs as they can't understand why something insured for £5000 doesn't have duty to be paid. Hold wax for months. Then eventually release.
It costs £000s to send back and forth due to insurance and is a fricken nightmare with customs.
When you buy wax for that kind of money, you might as well make a trip out of it and pick up the refill in person