disappointing mira shower

[helly18]

just had the bathroom reburbed and had installed a mira vie 8.5 kw shower to replace the trition T80si. When it was installed the piping was found to be 10mm and replaced with 15mm so i am thinking we should get better spray unfortunatley its not as good as the old one , would changing the shower head make any difference? went for a mira as thought it was better shower but now wishing we had stuck with the trition. Mains pressure is good.
thanks

 

[Jake1886]

8.5kw electric showers aren't great. Ideally you want a 9.5 or 10.5kw providing you have the right sized cable.

 

[Hugh Jaleak]

Was the pipework flushed out prior to installation? Could be debris in the filter on the water inlet.