I made 2 identical guitars as first projects, both using the same piece of mahogany for a body, the second one had a maple cap added, about 5mm thick. The mahogany bodies were about 40mm thick. Single cut, bolt on neck. Same circuits, same pickups. They sound quite different in the mid range.
The maple capped one has a lot more depth of tone, warmer, deeper bass and also stronger top end sparkle whereas the uncapped one has more mids.
I reckon less of this difference is down to the maple cap and more down to my learning from earlier mistakes and making the second (maple capped) one with a far better neck pocket rout and neck joint. So many variables to consider!