Wow EVGA are charging an extra £300 for a block mounted on the card...that seems a little OTT imo
It isn't quite that simple.
Firstly, it's £300 more than a reference/stock card, but it will have much higher clocks (the 980/780 HC's had stock clocks, which were roughly on par with Classified stock clocks), it's "only" £250 more than the SC version and will be clocked higher.
Secondly you get a water block and backplate (worth £100+) professionally installed as standard, no messing around if you have to RMA and no effort to install.
Thirdly, the EK produced EVGA blocks is actually better than EK's own brand blocks for the 980/Titan-X.
When you tally everything up it's ~£100 or less you would save by doing it all your self and to many of us it's not worth the agro. If I still had my GTX780 HC I would be all over one of these, but I already bought the GTX980 HC as I wasn't expecting these until summer.