I Have ev zx5 speaker with 600rms , is 300 watts enough to push the speaker or should i get a stronger amp

Solution
The difference in max volume between 300 and 600 watts will be 3db. Not a lot.
Use the 300 watt amp and if you find yourself clipping it (the amp may have LED indicators to show that) then consider a bigger amp but it won't get you that much more volume.