I have not seen the internal crossover and wiring so I cannot say how difficult it would be to work on these. However I do know form experience that the Duelund wire, Duelund & Jupiter grade capacitors can dramatically improve a speaker. If the DI has resistors, not sure, then more improvements can still be had.
Yes external crossovers are best as you get all the parts outside of the bombastic cab. I just don't know what's inside these so I cannot really give you a difficulty scale.
I am most intrigued with this speaker after doing some reading on them. Very happy to see the builder making such great speakers at an affordable price. Very exciting stuff.

