The MDX pix I have are with the stock fresnel lenses and one washer of spacing. I was able to get a lot of color out of it.

Keep in mind, color depends a lot on ambient lighting too. All the pictures I take are in a pretty dark area. If there's ambient lighting, it will wash out the colorband.

As for the output below the cutoff, it's about the same as the pics you posted for your retrofit. In some of the pictures it might look brighter, but the exposure and camera settings were different.