Wow, that was easy! Just one 5.8uf capacitor and some stand-offs (for the bigger Sonicap).
I didn't even disconnect the drivers. It made a nice buzzing sound when my soldering iron got close to the crossover . Anyway, put it together at lunch and it sounds pretty good. I bought the CS350 and the LS70s separately and I always thought the CS350 was a little lifeless compared to the LS70s. Not anymore! Nice for a second HT!