Hi MDAWSON
You asked about the top deck cut out, it all depends on what configuration you have trans or long?
If in longitude myself and Korgae have Been running the top deck cut out only in the front but all the way through. So cut the three ribs and then keep going until you separate the front.
If pictures are needed let me know. I found it to work the best for me on carpet. It just gives me the right amount of flex I need to run on carpet.
Hope that helps
Frank b