Fanch,
you have got it right...I am considering Ruf with Europipe exhaust!
I agree with you: when you modify a car, it's better to go for a well known tuner like Ruf (a bit expensive but...)
But I have to say that when i looked at 9ff, I was quite impressed by the datas and the look of the car (wheels, brakes, body kit, etc) and I wanted to know more.
As for the exhaust, don't know anything about performance but the 3 stage position is very cleaver
As for the Rallye de Paris, let me know something more . I am always interested in this kind of venues...

Thanks.

Ciao,
Andrea