A couple more points you may want to consider...

The pricing may well be different in France than here, but over here I believe that the $1500 wren is the manual start one, not the one with the built-in electric starter which ups the price to something like $2000. Not that there's necessarily anything wrong with the manual start - I'm just suggesting that if you compare apples to oranges, you should at least be aware of the differences

Since you have a limited budget, one thing you may want to consider is the availability of a suitable range of kits for a given turbine size. Hopefuly you will be able to reuse whichever turbine you buy in a multitude of models, and so you may want to ensure that your choice of turbine size does not adversely limit your choice of models to put it in.

Good luck no matter what you buy,

Gordon