The speaker mount lid that's sold on Luna's website cutout is a bit smaller than the stock Sur Ron battey lid.
In order to make it work with the speaker mount lid all you have to do is remove the excess plastic I will post some pictures
as well as make a video on it.
Basically I took my angle grinder to it and then took off the excess plastic and that's all. You can now use your speaker mount with the seat extenders.