Rakza Z carries a little bit more tackiness than a lot of other hybrid rubbers, such as G09C/D09C, Donic Bluegrip C1/C2, Xiom J&H H 52 etc So, moving to one of those or K3 etc SHOULD give you some more speed, depending on the sponge - how springy it is.
As NL said if you are not concerned about...