Everyone voting merc should be ashamed. Whats a non-performance family hauler have over a windsor-powered mustang!?
I can think of 10 reasons why Mustang
1. 5.0 sounds great,
2. and makes great power easily
3. due to huge aftermarket
4. Literally costs pennies to maintain
5. but they're already durable as hell so if you wanna be mean to one, it'll take it
6. 50 years of uninterrupted heritage
8. Great platform for track car (compared to a w123 anyway)
9. Camaraderie among the millions of other Mustang owners/muscle car aficionados
10. Anywhere else other than north america, it'd be a spectacle of a car... so you'd be famous
Also you're a damned commie if you pick a w123 over a Mustang (probably not but that's how I feel)
So roll up your sleeves and git 'er done!