The rear shocks from the Tacoma will not bolt up, the lower mounting hole (eyelet, I think its called) on the 4Runners is bigger than those on the Tacoma. The front Coilovers, assuming that's what you have should bolt in the same.
The coil springs are not screwed in, you just lower the axle enough, pop out the old springs and throw in the new ones and raise the axle back up. The shocks upper mounts are the same as the Tacoma in the rear.
I had the spidertrax installed when I was running my old stock size Firestone Destination M/T. I just wanted a wider stance. I'm currently running a different setup. Keeping the stock wheels, yeah biggest you can go is the 285/70R17's.