So far, I'm thinking I'll lower the car, get good tires and air them up quite a bit depending on what it currently has, do a rear wiper delete and a grille block. Not sure what the underside looks like on an insight so I might do some work there also. Has anyone ever hooked up an extra(or replaced) battery that you could charge at home to avoid charging the battery via engine power to get higher MPG?
Whatever tires you get, make sure they're LRRs and I would suggest keeping the OEM rims. Everybody likes the OEM Bridgestone Potenza RE92s, but I had a set of Michelin Energy Savers on my first Insight that were awesome too
Rear wiper delete is a popular mod, although I think the gains in mpg are negligible, that one is more for looks. I actually increased the length of my OEM wiper without taking a mpg hit. Since it sits vertically removing it really doesn't do much
The underside is pretty clean on an Insight, but throwing a fully belly pan on one makes it a lot cleaner. Several of us have done this mod, and I liked it on mine because it quieted a lot of the road noise
I think the big battery is too fragile to charge every night, but I'm pretty sure there are guys that do it anyway
Below are links to my two Insight threads, I did a lot of modding and had a lot of fun over the course of owning the two Insights. My son still drives the silver one and the belly pan is still on it. I lost track of Ron Burgundy after I traded it in, but that was one beautiful car!
With my gas savings, I bought this! (2000 Honda Insight)
With my continued gas savings I bought this! (2001 Insight)