When the use of FOD guards started I wasn't keen as the converted sieve looked cheap on aeroplanes where you could see the turbine. With ducted installations I started using them and I'm glad.
Over the last few weeks we have received a run of turbines with compressor damage where FOD's weren't fitted. Now JetCat have a nice moulded cover that looks good and supports the motor housing there is no excuse. People like Wren with the built in FOD lead the way and I think long term all manuafctures should do the same.
On my Inspiration I couldn't get a std FOD on the turbine as the turbine is already a bit long for the ducting, so I bought a cheap sieve and cut out the centre to glue into the removable inlet section. I'm glad I did as looking in the inlets after flying last weekend on our muddy field the pix shows the mud stuck to the screen.

Dw