Speaker Mods

Several years ago as a young struggling audiophile I bought a pair of Warfdale Diamonds. I was sceptical when I set them up, but I thought I'd give them a chance. I put an album on and listened. After only a few minutes I was ready to cry. I sold an okay pair of speakers to buy these and they sounded awful. I let them run for a while and since there was no noticeable improvement I realized I had to do something. I don't remember what the cable was anymore (this was about ten years ago) but I opened the cabinet and replaced all the wiring with either audioquest or monster cable???
When I put the speakers back on their stands the difference was unmistakeable. I did a "blindfold" trick with a friend who was also into listening. I played some familiar music for him while he couldn't see them. When he removed the blindfold he was floored that these little speakers sounded so good.
I have since moved on to bigger and better speakers and have thought about doing something with the cable but I'm worried about doing the wrong thing. When the speakers were cheap it wasn't intimidating, now it is.
Does anybody have any ideas about safe mods I could try on my Sony SS M7es speakers. They sound good now but I think they could be better.
Thanks for any insight you can offer.