Unfortunately, we did have to make a larger opening but it cut easily with a reciprocating saw as it’s just MDF like most of the other “woodwork” in the RV. They are not plug and play but Alliance had used the WAGO connectors so it was fairly easy.
I went a little different route in my 32rls. We don't use the OEM sound system. I installed a sound bar that sits on the shelf under the TV, with SW on shelf behind TV. I have a large library of phyiscal DVDs acquired over the years, so I thought I'd take along a sampling to keep in the camper and pop one in when we have poor connectivity. I got this Small BluRay Player from Amazon. Tucks away behind the TV when not in use.