I'd have to look up the receipt, but I think the male side was about 60€ and each female side was about 50€. BUT: I'd actually consider twice if I would want to mount it on my ECCI. They DO have a bit of play (which can be reduced to a very tiny amount using just a simple o-ring, sounds funny but it really does the job).
On the G25/G27 the QRs are just about perfect because they're reasonably cheap, but on my Frex they are borderline. I don't mind a bit of play, but it MAY be annoying to some people. Especially without the O-Ring mod. I don't feel any play when driving, but when playing a simple sine wave through David Tucker's wheel check it gets a little bit scary as you can definately see, feel and hear the noise of the play.
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About the communication with Juan: yeah, It sometimes takes a few days to get him to get back to you, but when he does it usually is quality feedback.
PS: what I really CAN recommend without any second thougts are his paddle shifters. They are quality, feel REALLY nice, look really good and are adjustable in about any way imaginable. I was sceptic about them after mounting the QR, but they indeed are quality and imho feel very comparable to the CSW BMW/F1 rim paddle shifters. Very crisp and very good haptic feedback. I love them and I wouldn't want to trade them for anything
And he sells them for a scary fair price (I think again about 50€ for the normal system and 80€ or so for a "double system" including 2 paddle shifters for up/down and 2 paddles for analog purposes (eiter be it clutch/clutch like in F1 cars or gas/brake for handicapped drivers) using hall sensors.