It sounds a bit muffled. The foam inside it has no real density though and is very lightweight. I do believe it is solid core though.Hey, @Epiphany ,
Do you mind going out to your car and tapping on your multimatic wing? Let us know if you think it sounds hollow. I would think if a wing had a foam core it wouldn't sound hollow. The best I can relate to is like tapping on a surfboard. It will sound light (not a dense solid core), but light (if that makes any sense).
Because I know some had the issue, including you as well Tom IIRC, I filled the open cavity in the aluminum insert you see up above. The GT4 wing endplates are not a perfect seal to the wing. Nothing like the factory CFTP wing with a bonded winglet. I left small voids for condensate, were it to occur. These wings can take in a bit of water from washing the car or if caught in a downpour. Now, not so much and the wing can still breathe if it has to.
If you look close at the next photo (it's hi res) you can actually see some daylight between the end of the wing and the end plate. All good as this is a race piece and is only overkill where it matters and the pretty stuff is secondary. Having adjustable plates makes it worth it to me.
Also note in the above photo, Multimatics method of upright to wing attachment. It uses a horizontal (better load bearing) flange as opposed the CFTP design which uses a rather narrow, vertical flange.
On Edit...I should probably do my due diligence here. For those that recognize and like what they see in the Multimatic hardware, the entire setup was about 3.5 times the cost of the Anderson. If you can scale value and cost, the two aren't far off from each other. Performance potential isn't the same but you already figured that into the equation.