congratulation, Adrianlle.
I'm not so brave as you. I let my JC to a dealer Eberspacher to mount a new airtronic D2.
I hope 2kW will be enough; you have 4kW...
I choice Eberspacher in place of Webasto because all technical information are "open" by Eberspacher.
Do you know this office
https://www.butlertechnik.com/ It seems they are very competent with websato and Eberspacher.
Greetings from Belgium.
vincent