The effect is astounding, with greater focus, detail and less haze and grain.
Yup, I’ve been doing this for years in my bi-wire configuration due to the urging of Chris Sommovigo from Black Cat, Stereovox, Stereolab, etc. and have experienced these same results along with notably tighter bass — I was shocked. While I might not go as far as calling the improvement “astounding,” it’s plenty significant enough that I’d never listen without the jumpers. I’m of the opinion that cost-effective jumpers from the likes of DH Labs, etc. are perfectly fine for this application, so I view this as a very worthwhile and cost-effective tweak.