[mpg_numbers_guy]

Chopping it would be cool, and you would definitely see gains from that, especially if you continued the chop with a tail at the end.

Brakes use friction to slow the car, but even when the brakes are not being engaged, the brakes are still dragging slightly. Brake reduction clips eliminate this and help you coast better. Braking distance may be affected slightly, so you would have to test it. I run brake reduction clips on my Insight and so far have experienced no issues in braking.

I'd have to double check, but I'm pretty sure people have run the 13" VX rims on Metros just fine. HX and Insight rims are 14" so if VX rims fit, HX and Insight rims would. If the Metro's bolt pattern is 4x100, the rims shouldn't have a problem clearing the calipers since 14" is a bit larger than 12".

The Bridgestone Potenza comes in the size 165/65R14 and is the stock tire size for the G1 Insight. It is generally thought to be one of the most fuel efficient tires out there. 165/65R14 is slightly larger than 145/80R12, so you would also get slightly taller gearing (6.2% taller: 2000 RPMs becomes ~1880 RPM), which would also improve economy.

^ although if the goal is an ultra cheap car, replacing tires/wheels may not be the best idea until you actually need to. HX/Insight rims will generally cost ~$200 for a set unless you are lucky, and the Bridgestones are generally $70-$110 per tire depending on seller.