With an enclosed replicator-1 clone (Qidi tech) I measured a plateau value of around 40-45 C inside the printer when printing at 100 C bed and 230 C nozzle. Reaching 108C in the FFCP seems like a very high value. How did you measure that? Was the air circulating (are you sure you were not measuring in a hot spot)?

In order to get good structure and detail, you should keep the ambient below 80C I think. Otherwise the stuff will remain rubbery and the nozzle will drag it up when laying down new plastic as it is quite viscous when leaving the nozzle?

The ceramic heater+fan+PID controller works very well as the fan moves the air around and gives a pretty equal temperature everywhere inside the printer.