OP, the 285/70/17 fits just fine in the spare area. I have my KO2s in that size mounted up with no issues. It's a wider tire than stock so it hangs down a little lower, but it's not evident nor a hinderance, IMO.
P/SL vs E? For me, the decision was load C, which is the middle ground. Es are too much for the 4runner when it comes to street driving -- they will transmit small bumps and cracks in the road more than C and especially P-rated tires.
So consider other tires that come in C load in the size you want. To me, most AT tires are pretty close in how they perform given the same load rating comparison. The differences aren't that huge, I think. So, it comes down to the looks of the tire and load rating for most people. If I HAD to choose the between P and E, I'd probably go E. I don't daily drive much, so durability offroad would take priority. If I did drive a lot more, I'd probably stick with P and ensure my spare was well-maintained in case there was an issue on the trail.
This is how I ended up with Load C KO2s in 285/70 flavor. They look good and aren't too stiff, although they are stiffer than P/SL so you will feel more NVH with them.
P/SL vs E? For me, the decision was load C, which is the middle ground. Es are too much for the 4runner when it comes to street driving -- they will transmit small bumps and cracks in the road more than C and especially P-rated tires.
So consider other tires that come in C load in the size you want. To me, most AT tires are pretty close in how they perform given the same load rating comparison. The differences aren't that huge, I think. So, it comes down to the looks of the tire and load rating for most people. If I HAD to choose the between P and E, I'd probably go E. I don't daily drive much, so durability offroad would take priority. If I did drive a lot more, I'd probably stick with P and ensure my spare was well-maintained in case there was an issue on the trail.
This is how I ended up with Load C KO2s in 285/70 flavor. They look good and aren't too stiff, although they are stiffer than P/SL so you will feel more NVH with them.