Adam, I enjoy your Commander posts immensely.
I was going to write a long, balanced post on why you should think very carefully about your mission profile & the futility of chasing around for old avgas guzzling twins w/bad avionics.
(well, at least with the Aerostar you'll be moving from a Harry S. Truman-era aircraft to a Lyndon B. Johnson-era aircraft)
But I think the previous posters covered this already. And you're a grown man & can make your own decisions. If you want an Aerostar & can afford it, I think you should just go ahead. What the hell, we only live once.
Only 2 things I'll say is this...
1. Never *ever* (!!!) borrow money to finance a private recreational aircraft. You could be in a world of financial hurt and impact your life outside flying. Adjust your spending to cover your budget.
2. Don't buy the Aerostar *before* you've sold the Commander. Managing 2 old aircraft at the same time will break your back, guaranteed.