I found the major offenders for noises on our 90 4runner were the power steering pump and wheel bearings. We just put new Michelin LTX's on it, so tire noise was out of the equation. I flushed out the power steering fluid which quieted things down quite a bit.
You might have them check the inner front wheel bearing. It never gets checked due to the fact that you need to replace the wheel seal to do it. Ours was fairly dry and way out of factory torque spec. You might try rotating your tires to see if it goes away.