Bottomsup: a fool and his money are easily parted indeed. Your electronics aquaintance is not misleading you on wasting money and you should search the archives. Most of these expensive power cords acts as filters (limiting musical extension), tone controls and/or spatial enhancers.
If you provide your system clean and abundant AC power, then cords in the $50-$75 range like the Absolute Power Cord (cryo'ed) and the Chris VenHaus (cryo'ed, too!) will be outstanding. The cryo'ed Absolute has outperformed $500-600 power cords. What a joke! I tried the VenHaus Flavor 4 in my Clear Image T4 power filter and it simply outshined. It's something I want to have.
As to your questions:
I guess what I am asking is: is there definitive proof that past a good reasonable power cord, can you make a difference? Can a cord be tested with any equipment to show that it is better? Thanks in advance.
1) Yes, but you need the proper setup that will allow you to tell it's the power cords that you're actually listening to. In Lak's system we tried two Flavor 4 one with cryo'ed and one gold plated Wattgate connectors (non cryo'ed) on his transport and there was a noticeable improvement in the music with the gold plated. That's how resolving Lak's system is...
2) No.
I spent a grand on cords without treating my room!