20k service should include but not be limited to
Engine Oil change(10min)
engine oil filter change(10min)
cabin air filter(15 min max)
i would probably change the air filter or clean it if you have a cleanable filter(5min/30min)
And for auto boys/girls i would change the spin on filter located under the air box(30min cuz of air box r/r)
Rotate tires and check pressure, check that all lights work
check brake rotors and lining
......think thats about it,
wiper fluid...wipers
oh and if you are running halogen headlamps I'd at least get some new best of the best halogens or a set of hid's.
The whole fiasco should take an hour and a half from onto jack stands to back onto the ground, materials should cost about 100 USD with air oil dsg and cabin filters, oil and new drain plug
I start by getting the lugs loose, then up on stands, tires off and lining inspect, rotate and drain oil while rotate tires, remove filter replace filter, dont forget o ring, only 18 ft lbs to re tighten. Replace new drain plug and crush washer, replace oil with appropriate grade and ammount for application, remove air box, if cleanable filter clean now, otherwise discard old one at this time, remove and replace dsg dilter, replace air box and new filter, 22 ft lbs on dsg cap. Put car back on ground, retighten lug nuts and replace cabin filter under/next to glove box passenger footwell.