Here are two links to the relevant parts pages that are searchable.
Where did you find any markings on the gearbox that relate to :
CWA/DVY/EFD classification letter GDW/GFW ?
see post #3 above for locations:
" on the side of the gearbox case = +GF+WD 21561" What does this mean?
Porsche Boxster Parts
G86.00 Gears And Shafts -99 G86.01 Transmission 00- Cwa/dvy/efd Classification Letter Gdw/gfw Attention