I have no BOA relationship, but this might push me towards it. By my calculations, I'd get:
20K signup
50K spend bonus
18K from spend
5K from AU
93K miles after 6 months, with the ability to earn another 12K (7500 + 4500 from spend) with an additional $3K spend, or another 34.5K (15K + 19.5K from spend) with an additional $13K spend, for a total after 12 months of 128K miles on $25K spend (5x).