I had a converted 201 he made in my hands at the Kampenhout GP this year - the flex was considerable (it felt like twisting a sheet of paper compared to a girder/normal chassis)
That thing will give awesome grip, and thanks to the sidepods that are flexible yet run over the entire length of the chassis it should not bend (or with CF, break) at the sight of a jump like a C4.1 does
Only concern I'd have is if the chassis flex won't blunt the sharpness of the car's handling... but that's something you'd have to experience to judge.
Detail of the conversion imo was also really nice: The plate was machined into to make the battery sit lower, the sidepods blend in nicely with the rest of the car. 200 euros is a big price to pay, but this is coming from a single comment. I would just contact him to see where the pricing it at now, and if there are any UK drivers (or any upcoming events) where there might be an opportunity to try one out.