Do different speaker stands can really make a big sound improvement?

Stand they do make a difference.

I can attest to an audible improvement with my HL5+XD’s when I replaced my height appropriate but “massy” stands with the TonTragger recommended option. I wouldn’t say the same about more typical rigid speakers I’ve used previously. Cost was about $750 CAN extra used and well worth it to me. 

Absolutely they can; some stands are necessary for some standmount speakers to sound their best. I had those kinds of stands for Harbeths, but I sold both Harbeths and their stands as they were not giving me the kind of sound I prefer.... 

roadcykler,

If you think speaker stands and cables make no difference you really need to get your ears checked because the Townshend podiums make such a huge difference because they stop all vibration from going into the speaker, It's like you upgraded to more expensive electronics and the same with cables, OCC single crystal is the best conductor for audio and it's been proven for over 50 years, far superior to anything cheap OFC.

Of course they make a difference, cables make a difference, weather, humidity, everything matters. You can spend enormous amounts of money building the perfect listening room with all the perfect gear and accessories then you walk in the room and screw up the sound just by being there. Many companies and people make quite a bit of money selling dreams, they only have to convince would be buyers that their products are so much better than any others, fancy words, pretty pictures and unsubstantiated claims is all it takes to convince someone who wants to waste money. All kinds of ocean front property has been sold in Arizona as well as several bridges, I'm off to buy the Brooklyn to go along with my Golden Gate.