I have a similar situation on my 1981 E-36 Ron Holland, only one of the previous owners took a hand at reflooring by himself. The thickness of the wood used for flooring is a big issue you should examine before you start. The teak and holly used in my boat is about 1/4 to 1/2 inch thinner than the original. I know this because the installed furniture has a slight gap at the bottom. I looked at it carefully and realize that there is infact marine ply underlayment below the teak and holly sole. I think theprevious owner used the wrong thickness marine ply. At some point I am planing to fix this.
Any suggestions about cabin top re-coring, and relplacement of headliner?
Steve