I recently picked up a grey Ventus with 4Tcore in a stiff flex. I spined it and have been using it in my Ping driver. My shaft that I have used with this head has been a Kuro Kage TiNi stiff. Been using that shaft for 2 years. I believe that Ventus to be stiffer and a bit lower in ball flight. Will be switching back to the KK in the near future as I like the feel of that shaft and probably know it better. That said, I have also been demoing the real Ventus blue with velocore stiff in a Mavrik lately. Probably played 2 rounds and had some range time with it. My very limited observation is that the real Ventus feels better to me. Can't really make a head to head comparison as I am using Ping vs Callaway. Must say the Mavrik and Ventus is probably longer but it seems I really have to go after the ball hard. I think the Ventus is a bit to stiff for my 95 - 100 mph swing. Would like to try ther Ventus in a regular flex but regrettably my club does not carry that shaft in the fitting cart. Am currently playing to a 6 hndcp just for background.