Necessary supplies:

• Oil of choice, ~6.5 quarts for V6, ~3.7-3.9 quarts for 1.8
• Filter of choice (Mann, OE, K&N. About $10 for V6, $5 for 1.8)
• Oil filter wrench, (strap-type: Walmart, $3)
• Oil drainage pan (10-15 qt. capacity, Walmart $5-$8)
• Ramps (recommended: Rhino Ramps, Walmart $30)
• Flathead screwdriver
• 19mm socket or open wrench

Optional supplies:

• Soft metal “crush washer”, either 14mm or 26mm depending on your drain plug
• Rubber gloves
• Rags
• Funnel

1. Run engine for approximately 2-3 minutes to warm oil, then open hood.
2. Position ramps in front of tires and drive car gently up to the stop.
3. Leave car in first gear (or P) and apply parking brake.
4. Place a chock behind rear tire(s) (or brick, 2x4, etc).
5. Remove plastic underbody cover—there are two plastic screws in each wheel well, 4-6 more towards the center of the car, and a small nut front and center. All of the screws should come out after ½ to 1 full turn. Set the screws aside.
6. In the V6, the oil filter will be plainly visible underneath. In the 1.8t, it’s about midway up the engine on the right side (facing the engine). It may be a stretch to go in from underneath, but you can remove the coolant reservoir from its housing and come in from the top if necessary.
7. To remove filter, first position the drainage pan and/or a rag under the filter. Attach filter wrench at the base of filter and smoothly twist it counterclockwise (normally threaded).
8. Clean filter area of dirty oil, and be sure the rubber seal came off WITH the filter. If not, be sure to remove it from the engine before installing new filter.
9. Below the car, remove the 19mm drain plug from the oil pan (again, the crush washer on your car could be either 14mm OR 26mm). The oil pan is located with a foot of the lower front bumper area, and the plug will drain to the right, nearly perpendicular to the ground (facing the engine).
10. Wait 20-30 minutes while the oil drains from the pan.
11. Apply thin coat of fresh oil to new filter’s rubber gasket, and twist on new filter by hand. Don’t overdo it!
12. Replace drain plug (30Nm/22 lb-ft if you have a TW), including a fresh crush washer to ensure a tight seal (not crucial, but recommended. Re-using old washer could allow slight leak).
13. Fill up car with fresh oil: Use a ½ quart less than needed, then start the car and let it run for 2-3 minutes. If there is oil spewing all over the place, check the seal on the filter and be sure drain plug is installed properly.
14. Replace the belly pan. Be sure that all screws line up properly and that the edges of the pan are completely enclosed by the lower bumper and wheel well liners.
15. Remove wheel chock(s) and back off ramps.
16. Turn the car off and wait 10-15 minutes for oil to return to pan.
17. Check dipstick, and carefully add more oil until you reach the MAX level. ’98 and ’99 1.8t engines need 3.7 quarts, so be especially careful at this stage. Underfilling is better than overfilling—you can always add more oil if needed.

Many thanks to DippinPete, Matt07, B5Skvir, pass-variant, et al, for their contributions.
-Ash (ashman78)