I had the kuhmo 155/80/13s on my 92 VX and just replaced them with Hankook Millage Plus 175/70/13. Although I haven't been logging miles & calculating MPG, my perception is that the car accelerates slower, rides harder and gets lower MPG with the new tires...YMMV
lol...thanks for the update. I've filled up maybe twice on these tires and wheels and I've seen no real difference in fuel economy yet (averaging 34mpg). However, I'm using AC like a crazy man and I'm also driving around 80 mph on the interstate.
...so basically i'm not really hypermiling, other than my city driving. If I ever break 36.6 (my record with steel wheels and my 175's), I'll let everyone know. This will probably happen sometime in January of next year, when its not so freakishly hot in Florida.
Oh, and I do notice a change in how acceleration feels. But then again, they're new tires, balanced and everything, versus some super old tires unbalanced. And they're nicer tires than the ones I had on my steel wheels, so everything's really improved (accel, braking, ride quality, handling, high speed stability, road noise, ease of turning).