I'm gonna have to disagree with the Cat5, 5e, 6 item. I know that technically, there is a huge difference between the ethernet cables themselves. BUT as far as the FBV Shortboard MKii, and the Express (mki) there is NO difference. For me anyway.
I used at Cat5, 5e, and 6. There is NO difference in sound, quality, feedback, buzz, or anything. For me.
There are thousands of choices for Cat5e and Cat6 cables to purchase. But regular old Cat5 is not that easy to find, you search for cat5, and everyone ends up selling you a Cat5e, or Cat6. I wanted to use the Flat Cat5 cables, and there all 5e or 6. i have tested all of the different styles (cat5, 5e, 6) and the Cat6 works fine. So, for anyone else looking for a new cable, the Cat6 works fine. I even updated the firmware on my amps and pedal with the Cat6, worked perfect. (FBV SHortboard MKii and FBV Express MKi)
I read that people state there are different impedance between Cat5 and Cat6, i understand that. But how that affects the FBV pedals, i don't know. I did not see ANY difference in any function of the pedals with a Cat6 vs Cat5e or Cat5. I don't mean to start a war, just informational if anyone ends up like me and needs/want a new/different cable for their pedal.
And the TRS cables... I purchased these: https://www.amazon.com/gp/product/B00HXB3TLQ/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
I could not tell the difference between the TRS cables above and the 16awg speaker (mono) cables. It's not like its a DTS 5.1 system or anything, so comparing the stereo effects output, the differences were not distinguishable. I will agree with TRS cables being balanced, and that it does sound "cleaner" with TRS cables. And the manual does say to use TRS cables. I wish the manual would state what gauge cables to use. And i can find a million parts for the Line 6 IV amps, but not replacement TRS cables.
I definitely agree with NOT using regular guitar chords for hooking the head up to the cabinet. They sound Terrible, extremely terrible.