[skater]

1.
Clutch - slave cylinder and flywheel. For the clutch, BillJ sells an SVT clutch kit that's cheaper than a stock clutch and includes the slave for like $300 shipped. You can pick up a new SVT flywheel for less than it costs to resurface the old one.

Spark plugs - Motorcraft or Autolite only.

Plug wires - Motorcraft stock only, even the Ford Racing wires sometimes cause problems.

2. At 200K, that's a lot of miles. I'd consider looking into a new diff for it - they seem to go at odd intervals. I think otherwise the MTX is basically a good transaxle, especially if you aren't pumping a ton of power through it.

3. Good question. I don't know if anyone sells just the boots. FYI, although you probably aren't looking to spend extra money now: If you look in the Group Buys section, there's a guy selling entire halfshafts for the car for decent prices - I replaced my passenger halfshaft with one of his and they work fine.