Have you been surprised by power cable changes? s

Having been listening to music for over 30 years the tweak I had resisted was power cables and mains blocks. 

I took the plunge spent £400 on mains cables and a mains block through Mark Grant cables in the UK. All hand made. It was easy for me as he lives 15 mins away.

The quality of the product is excellent the sound difference, just tighter, clearer, no noise,  it is like lifting a veil off the speakers the whole sound just seems clearer, greater separation and increasing the width, height and depth.

I recommend you look at your power cables and mains block rather than spend £0000's on new boxes. I wish I had taken the plunge years ago. I have never heard Marc Cohn or Jackson Browne sound so good. 

I have a nice set up. Amplifiers Croft Epoch Elite and Croft Twinstar 1 both modified by Glenn Croft,  Melco Streamer, Exposure Dac and Piega Classic 40.2 speakers with Lfd Speaker cable and BK sub Xxl 400. I could not be happier.

Enjoy the music. 

Has anybody tried to “reverse” ICs or speaker cables to see if you can identify a difference?

Why don't you just try it and hear for yourself?
Millercarbon, why are you getting so defensive? If you could rationalize how your treasured power cords supposedly improve sound quality as you say,  I’d take you seriously. So the ball’s in your court to explain how these magical power cords supposedly work. And..... go!
The discussion thus far has been positive re the power cables. I have no experience in this field and have no intention to find out why they work. All I know it the difference is not subtle.  There is such a gain using them, all I intended was to show my surprise by how much for the outlay. I will leave the science to others. I can honestly say I wish I not tried to understand years ago and taken the plunge. 
millercarbon: it was my observation, years ago, that more expensive (not available to me in those years) speaker cables and interconnects were "start broken in" (45-50 hrs or so) by the manufacturer, and and were then labelled with printed arrows on the cable jacket, showing the direction for installation from CD to pre/integrated/power and integrated/power to speakers. I have never experimented with reversing this - why would I? Obviously you can't reverse the power cable because of the differing connections... I personally think the reason that those listeners who do not hear the impact of swapping 'it' out,  ('it' being) power cables, speaker cables or interconnects, is because the amount of time necessary for 'it' to fully break in is much more than they are willing to wait. I figure continuous play of at least 750 hrs - yes, a full month, is not an unreasonable amount of time before reasonable comparison is possible, and if a 'it' is not in use for several days or longer, 'it' will require at least 72 hrs of re-break-in ('it' has a memory? I believe so...) before it is back up to snuff, its full potential. Now I'm sure some/several/all those much more astute, learnered, experienced than me will scoff at my practice - that's fine: keep buying new products (from equipment to cables), throw it into your system without correct break-in efforts, be disappointed and drop it onto the open market at 1/2 the origional cost for me/others to snap-up and 'treat' it as it should have been. I believe the used market is misnamed: it should be called PRE-OWNED ('cause over the years, most of what I purchased USED was barely broken in...)