Guitar wiring.. Is this dangerous???

[William Walker <billwalker@baymoon.com>]

Only when doing it in the bathtub...  but seriously, sounds like your  
sustainer pickup has a ground issue  as inconvenient as it is, I would  
use the best audio cable you can afford with your regular guitar  
output jack, and not use the GK cable to pass strait audio, yep, use  
two cables from your guitar. you can duct tape them together if this  
idea sounds to cluttered. Why, a simple A/B comparison will reveal a  
more robust full range sound with the regular guitar lead, and a  
decidedly  thinner sound with the GK cable which uses one tiny strand  
of its cable to pass guitar audio. You might also get rid of the  
ground hum in the process.
2 cent from a recovering guitar synthesist (5 years of sobriety)
 Bill

PS any more enthusiastic reviews of the GR55 and I may fall off the  
wagon.