Just to clarify one thing. My Wren 160 had no problems with the compressor. In my case the turbine wheel shed a blade & destroyed the engine.
After some debate, Wren supplied me with a new turbine. They were eventually professional in this case.
I have had problems with them in the past with another 160 I had, & was not satisfied with their service & charges on more than one occasion.
I no longer have any Wren turbines & now use other makes.