x2 on buying OE parts for critical applications like these. The only other place Iwould probably buy parts would be NAPA. At least there, the guys at the desk are grizzled parts guys, just like the guys at American Toyota (or most other dedicated parts places).
Some other tips for a first timer:
1. Take out the battery and battery tray. It will make life a lot easier for you especially when you have to deal with the alternator adjusting bolt that goes in horizontally from the USDS wheel well.
2. Make sure you replace the rotor, the dizzy cap, as well as the wires and spark plugs at the same time. It's generally good to keep them all on the same replacement schedule so you don't have to think to yourself "when did I replace this?" etc.
3. The #6 spark plug and wire sometimes gives people trouble. Take the 2-12mm bolts for the wiring harness and the 2 10mm bolts for the heater valve out and get those things out of the way to give you more space to work. While the harness is detached, take a good look at it and see how the heat taping looks. The EGR valve right underneath it is a very high temp. application (approaching 1000 degrees. If needed, go to a race car store and replace with some aluminum taping or some other heat resistant material.
4. Use anti-seize on the spark plug threads.
5. Be careful with the dizzy cap rubber packing. Don't rip it.
6. Put di-electric on the plug ends--not the spark ends, but the ends that go into the wire. Also put some di-electric on the ends of the wires where they attach to the dizzy cap.
7. I would recommend replacing the idler pulley underneath the alternator at the same time...maybe even the pulley for the AC condensor tightener--the one that the bolt goes through from the bottom. These are fast wear items and a good "while I am in here" work.
8. You do not have to take the fan or the fan shroud off to do this work. Snake the belts over the fan and clutch.
9. This is a good time to replace your fan clutch if you haven't already.
10. Be careful to not over tighten the belts. They should have about 1/2" of play at their centers between pulleys--when I mean play, I mean the ability to push on them up and down--should be about 1/2" each way.
11. The belts should not ride deep in the pulley grooves. There should be a small bit of space between the bottom of the belts and the bottom of the pulley valleys.
12. Do not use cogged belts--they tend to make lots of noise as opposed to the non-cogged OEM belts.
Good luck.
-o-