I'd replace virtually every piece of rubber that holds air, water, gas, or oil. Tubes, hoses, o-rings, bushings, the lot of it. Apart from the tires, that'll set you back less than $500, maybe closer to $300. Some clever person could probably make a few bucks by selling a labeled kit of these items all together.
Another +1 on injector cleaning at mrinjector, and the tires of course.