For what i understand, wipaire is working on the stc for the Grand Caravan and most likely they'll use the wipline 8750. I got the information that there is Grands with floats but after doing a lot of research, my guess is that whoever saw that airplane, assumed it was a 208B when in reality it was a 208. I spoke with a guy from Kenmoreair and he told me that there is no one around with an STC for the Grand and the only company working on that project is wipaire.
Thank you all for your help