This is true. Original Bougicord is better than most aftermarket crap cables. I've actually seen folks lose torque after changing cables.
Yes.. but you need to know what to buy and whether suitable for your car or not. Back then when I was messing with my car, I changed to this "Best I-Cable" brand plug cables. Although the name is highly amusing and suspicious, I got them at a cheap price after the manufacturer actually advertised here in ZTH (I cannot find the chat anymore) and I challenged them to do an actual test using my car as the guinea pig. Pre and post cable dyno comparison.
The cable did actually increase my torque a bit and smoothened out the entire graph before and after. And I made it a point to give the car a week or two of running with the cables before doing the dyno. The Siemens VDO is notorious for adapting to anything added to it, like useless air-leaking devices and some piggy-backs. And to add icing to the cake, I actually took out the cable and reinstalled the ori cable and the difference was instant. Again, after a week of running ori again I did the dyno once again. The power loss was apparent. Not huge figures like 10-20nm of torque different, but something like 4-5nm of torque which is a lot when you don't have much to begin with. My car with the cable was running something like 14 or 15 kgm of torque in its "final" form.