I have that exact pack plate, it was modified but I just need to peel of the photo and it would be like new, if you decide to go EK you can have it if you want. My 290x died and I don't need it.This is what it looks like now.
Don't even think delidding is needed. The chip is very cool under water, they don't have the problems other intel chips have had at all. mine idols around 20c and under full load at 4.3 got to around 50c but could nt get it to heat up enough to even ramp up the fans. even at higher overclocks I don't think it will do any good to delid it.
I did some gaming with my MSI 390 and with everything maxed out in Crysis 3 at 1080p I hit a max of 68c. It was butter smooth but I guess it should be at 1080p. When I get a 1440p monitor I am expecting it to tax the card a lot more but I am as happy as I could be with it for now.