Are upgraded power cables really worth the money?

Yes - you will find that good power cables make a similar difference to introducing good speaker cables to your system for the first time.

Imperative upgrade imho. I recall the day a few years ago when I first introduced a decent power-bar (appr. $ 150) and 2 after-market cords (each appr. $ 100) in my system. The dealer had lent the gear to me over the weekend and I never returned it; it was like drinking a nice cool beer from an appropriate glass when you're really thirsty instead of the bottle-neck or a can.
Try and find someone who will lend you cords for auditioning before you open your wallet. I think you'll find it rewarding if you went for something in the price range I cited. VooDoo Cable's entry level could be one starting point. One of many, I'm sure, but I have found Bruce's recommendations very precise and valuable, surely an advantage as you may have to lend special attention to the sub.
Good luck.

In my system, the power cords made the most significant difference. I started at the CDP with my best cord and added one at a time and listening to the same song over and over til I got the speaker cables added. I tested several cords and cables and the Shunyata got the place in my system. You could spend quited a bit on Shunyata power cords and they are worth it IMO. A budget plan for Shunyata would be an old Cobra Red label or python for the cdp, and a Diamond back for the integrated. this would be under $700 used here. You could go with python helix if you have more budget and put them everywhere like I did. I started with the budget cords I mentioned and eventually sold and replaced with new helix. you could get more lower on the budget. What would your budget be on PC's.

beerdraft