I am in no way an expert, but i would suggest you find out what is around in nearby clubs, i notcied you said no one in your present club flies turbines.
The WREN AND JETCAT, both are good turbines, i use the jetcat as personally i wanted an all in package, the JETCAT has a governer so it is almost plug and play so to speak,
Some say the WREN sound better and are smoother and have mnore power, but i have only watched a Vario acrobatic with a wren i havent flown one before.
The thing going for the wren is the customer service, but you are closer to jetcat germany than we are in the UK, so the delivery timings might be better in france.
I would do as you are doing, fly it as a pod and boom first, i am flying the HOTCAT, which has now been surpassed by the Powercat,
I have seen the wren engines in the predator, Vario Acrobatic, and Quatro.
All The Best