i would like to put bigger mud terrains on my truck but iam concerned it might be to much for the runner is there any sugesstions

Shouldn't be a problem for the V6 as long as they are not freakishly huge. I assume your's is a standard transmission.

You will notice a drop in fuel efficiency though so be prepared. As well, your speedometer will indicate a slower speed but you will be actually travelling faster (and your odometer will rack-up less miles as well).

I used to compete in off-road competitions here in Canada and I can say without a doubt that tires will account for less than 1/2 of the vehicle performance (for most off road applications in the mountains). Driver experience and skill (and a winch...lol) are the best investment.

The Yokohama tires used to come stock on 4Runners (on my '92 anyways). Don't need anything bigger, you're only gaining an inch.