The rims I replaced the stock ones with weigh 11.9 lbs., I believe stock insight rims are 10.5 lbs. ? FEATHER
I had to replace the stock rims because I hit a pot hole in town and it bent 2 of the rims and it was too expensive to replace with factory rims....
I also went with a slightly larger wider tire. The car is so much more stable and safer at highway speeds now, well worth the 0.3 decrease in average Mpg.
As far as mileage with the new rims and tires. I fill it up 10.6 gallons, drive to the Canadian border to visit family at 442 miles exactly round trip, plus a little driving around up there, say 30 miles and get back to Portland with 1/4 tank. So, approx. 7.95 gallons used, and 2.65 gallons when I get back...= 59.37 MPG, and that is doing highway speeds up the I-5 at around 75-80 MPH. I would trade safety and stability for MPG any day. Last time I drove the I-5 with the stock rims and potenzas a passing semi wind blast nearly pushed the car off the road.
The mileage is good but the market is soft on these cars right now. You might have gotten that much 2 years ago but not now. There is an '04 with the same miles at $8200 Honda : Insight DX w/ Ice Cold Air Conditioning in Honda | eBay Motors but he hasn't been able to sell it for a while, plus its an automatic. And most buyers who are willing to pay that much want everything stock.