Feel like I write this every week, but here's a quick test:
Jack your front end up, and leave the tires on. Grab the tire at 9 o clock and 3 o clock and push/pull your tire back and fourth. If there is play, your tie rods are worn.
Try again at 12 and 6, and if there is play, your upper/lower ball joints are at fault.
I've never replaced the inner tie rods, but I've heard they are difficult to replace. Don't quote me on that though. Try doing a search.
Replacing the lower ball joints, steering rack bushings and outer tie rods are easy though and all pretty cheap. I dont see how new UCA's (I'm assuming you meant new upper ball joints) could increase your steering performance. If anything it would get worse using a uni-ball rather than a stock ball joint. But, depending on your mileage and how deep you want to dig, I suppose you could.
I bought a ball joint press kit from Total Chaos to help with removing and reinstalling the upper ball joints. You can just as easily do it with a ball joint removal press though without the "jig".
Another thing you may be interested in is to replace the lower control arm BUSHINGS. However you will need access to a press to get them in and out.