You have a unicorn, and owning it only makes sense if you plan to keep it a long time. Otherwise, $35k for a 3-year old 3 Series is way too much to spend in terms of market value. FWIW, I bought out the lease on my BTO 535d at the same point in its life for $34k and have taken a huge bath on resale value.
Check out the search for pre-owned cars on BMWUSA.com to get a sense of value.
2014 535d, M Sport, Space Gray/Mocha Nappa
2007 530i, White/Black, 6MT
2001 530i, Orient Blue/Beige, 5MT
1994 325is, White/Black 5MT
1984 325e, White/Black 5MT
1983 318i, Delphin/Beige 4MT
Last edited by Robert A; 10-02-2019 at 09:30 PM.