I just bought a 2018 A4 with low miles (3,610) -- wondering if any of you have advice about warranties. Specifically, would you advise getting the $1000 maintenance service warranty that covers me for an extra 3 years beyond the first year, and / or the $4000 bumper to bumper warranty that extends my normal 4-year warranty another 6 years. Would really appreciate some help on these. Thanks!