Swapping to spherical bearings will actually add to the wear on other systems in the car because it directly transfers forces. Poly acts like a spring and can bind, so it effectively ups the spring rate of whatever system it's in. It can deflect for sure, but I would bet that going spherical (which reduces overall spring rate) will have the same, if not more tire wear. Wheel bearings go out on those cars on r-comps. Swap to the 5x114 knuckles to solve this. It's not the poly that's hurting those.
I have run sphericals in the rear suspension for years without wallowing out any holes. I recently sphericaled the OEM arms up front but expect the same results of "I need a tad more spring rate".
Like Ham said, there's a lot of common issues in SM, and until you spend some time massaging the inner and outer fenders you'll rub, and even then you'll want more grip so you'll go to a bigger tire, which will rub again, so you'll modify again