I was wondering if changing the tires on my 93 4runner (to smaller ones)would increase the horsepower and how much I would notice it. Also they are stock 31x10.5 r15, what size could I go down to with the stock rims or should I try different rims as well?

 

FYI,
be carefull whenmessing with the size too much as you may create an unsafe imbalance as i'm i'm assuming the yota engineers carefully speced out the tire size/width/height to avoid flipovers ect... all i'm saying is try to keep it as close as possible to original..... my 99 3.4L runs on larger265/70/16 tires( w/16" rims)and thiswas an optional for that year and the"standard" size that came with the truck was a smaller 225 75 15" (15" rims)