I plan on using the triple SU since all 3 carbs have been completely rebuilt, matched internally and set up for a big six in my Dart wagon. Based on what I've read on an Aussie forum I'm on, they run pretty strong. I'm still on the planning stage for the engine, so I personally don't know how they'll run - I will report back when I get to that point. Was thinking about doing a 340 for my GT convertible but might have to re-consider and go with the Webers (since the GT was an original slant car).
Yes, they're definitely some sweet eye candy! You're right about neither manifold being able to mate to a stock exhaust manifold. Each will require headers. No alignment issues at all.