Need help w/ Dr Gas order

I'm ready now. It's currently a 302 w/o much mods except Air Gap and Demon 650 & ignition. Hopefully to be swapped for a HiPo351 (alum Dart if business goes as planned) next year. I'd like to re-use most of the exhaust system if possible. Don't know if that will be reasonable. This is a street corner carver application so speed bump clearance is important. I also need recomendations for shorty headers. I'm ordering the TCP subframe set-up so exhaust should work with it.

So I need to decide size first. I'm just guessing at 2.5" What do you think?

Do I get the Universal crossover kit or the "Custom Tandem"?

I'm assuming that I'l need pair of ball & cone connectors for the header-crossover connection and another pair for the long tube-muffler connection. Do I need another pair for the muffler-tailpipe connection?

What about the frame clearance tubes that Dr Gas offers? Would they be helpful? Or does the ground clearance become more of a subframe issue?

Mufflers- I'm thinking the Spintech Sportsman Street XL. They look like the largest, quietest ones that Dr Gas has to offer and maybe have a more unique sound than the standard Flowmasters. Any opinion?

How about hangers? Should I just let my exhaust fabricator deal with this or is there something I should know?

Anything I've forgotten?

Thanks