CB Coax, replace with oem, or go with aftermarket?

Should I buy the kit from Volvo and replace the coax inside the mirror heads, or bypass all that and run better coax, and mount the antennas differently?
My truck does have the covers on the mirror brackets so I would have to come up with a different place to mount them. I kind of like the body mount antenna's better than mirror mounts anyway.
Any other advice?
I know the am/fm use the same antenna's, but I have SiriusXM.

 

Good advice, thank you. I get down to Barkeyville PA occasionally, I think there's a shop there.

 

Anybody have experience with these side body mounts? LGXM2 - Firestik Firefly NGP No Ground Plane CB Antenna Kit I might just eliminate all the mirror bracket stuff.