I think $600 is too much. You can buy axles at alloemvolvoparts.com for $128 each (I was looking at these last week). Tie-rod ends are only about $20. I would think if you're confident enough to do brakes, then an axle isn't anymore difficult. However, I had to replace a front hub assembly last weekend and had a hell of a time getting the axle out of the hub: 8lb sledgehammer pounding as hard as I could. I had to improvise quite a bit to restore the threads of the driveaxle before the new nut would fit, but I got it done. So, while I didn't actually replace the axle, I had given a great deal of thought about doing it before I decided I would be better off fixing my current one. You should be able to do it. Tie-rod ends are easy and on the '93 you can replace the ball joints which are probably worn out if not previously replaced. Also, check your brake rotors while you have everything apart because it would be a really convenient time to replace them. The hub bearing, too, for that matter, but if they're alright, no need to get carried away.