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. 

markgwYes, I'd totally agree with this.  A lot of it is about transients and the quick draw on the power that is needed at the bass end.  The straw analogy was good; wire gauge I think is vitally important for the equipment to perform at its best. 
Yes I’ve been surprised by power cords. It’s all about experimentation in most cases and when I’ve swapped a thicker or more well constructed power cord for the stock cable, I don’t want to be surprised because I think (thought?) that it was a bunch of nothing.  But there was a change. And often I liked the change. Ditto for interconnects. I even tried some vibration control for the first time by just experimenting with small weights on my DAC to see how it affected sound. I was kinda shocked....  Some extra layers and depth opened up in the music that I swear to god were not there before. When I take the weight off, the veil goes back on.  Small changes can have big impacts. 
@ypingping-  Apparently, that post contained too much fact for the, "moderators"(or someone's tender feelings).    Obviously, the truth regarding Science/Physics just doesn't wash in these threads.  I suppose this will be deleted as well, though it contains no profanity and doesn't violate any other of the site's, "policies."   Pathetic!
I have training in electrical engineering as part of one of my doctorates - I am a professor at a medical school. I am an experimentalist as well as a theorist. 

My audio system is relatively expensive, all digital with a master clock. The power cord and the ground station made a huge difference, as did the power cord to the master clock and the BNC digital cable from the master clock to the DAC/CD/SACD/network player configuration. 

My experience was that the line was quite noisy including injection of noise from the components, but now there is no noise and all recordings (streamed or from a hard copy) sound spectacular. I think that folks with very inexpensive audio systems may not experience the benefit of expensive cords and many who are critical of such upgrades do not actually listen to music with the same intensity that we do...