Magnepan MG20 tweaks ?

Hello,

I have MG-20's in my system and would like to improve the sound.
I power them with a pair of Pass Labs X600 and I'm very happy of the sound!

I have questions for Maggie owners :
-What are the best way to improve the passive x-over (to replace caps, inductor... internal wire?).
-What type of cables are you recommanding from the MG X-over and the speakers ? (cardas seems to be very appreciate).
I'm leaving in Europe so please give me the links to see the products in Internet.
Thanks,
All the Best. Laurent