Thanks Buddy. Actually I tried the automatic distortion correction in CC/ Camera raw, but that didn't give the wanted results (over-correction). I just straightened the horizon, and applied a very slight barrel-correction and some vignetting (wide open). (it's not 100% perfect in my eyes)
Most important with the 17mm is get the framing right when taking the shot, a lot depends on how perspective is used, a few cm. movement can change it.