Playing Kapustin slower. . . always good advice. 
hi Goldentone I tend to agree , but it has to be within reason, there is too slow , and w the Kap, one needs to try and abstain from romanticizing it too much , Ie excess rubato and tempo expansion and contraction need to be kept in check and subtle if at all!
Ie the Elaine Rodrigues recording , she's a good pianist, well regarded and its earned but her prelude etude , its ,um, well, ...here see for yourself, not my thing .....
Then there is a place for excitement and super agility and briskness, the no 8 for example , still many a pianist miss places of great expression , here this guy is awesome there's good videos of him in the competition scene , he's from Belarus. I used to think I had a favorite recording of this one and that I had heard pretty much the best way it could probably be done by a few pianists, then I came across this, and , well here, speaks for itself...esp around 1:41 + GAH! so good!!!!