Regarding "bumpsteer" -
Tires do NOT cause bumpsteer! Good sticky tires may make the bumpsteer more noticable, but they do NOT cause it.
Bumpsteer is "toe change during suspension travel". If you have toe change after a tire swap, you had it before the tire swap as well. Don't blame the tires for bad suspension geometry.
So what you are saying is wider tires on his car with his stock components, no modifications or upgrades, and unknown miles will amplify any deficiencies in his system? Sounds familiar. I totally agree.
so how wise would it be to use a bigger tire in the rear? dad's not liking it but i kinda do. i could use the 195/70s in front while using a 215 or 225 in the back.
you need to get that car in the 2000's,staggered tires are not going to hurt anything. Although i wouldnt mix a 70 series on the front and 60 series on the rear.