I had an OCA cover on an optimax in the past it dulled the compressor sound from the Opti a fraction and kept bait juice off the paint. Worth the $$$? I don’t know.
I intend to put one on the etec but it has not reached top of priority list as yet.
I see ocean south now make model specific leave on covers for most engines but have not seen one in the flesh. Around $120 I think but could be wrong.
Until then a quick spray with quick detailer after each trip seems to be keeping it in good nick.
It was my pleasure being no help at all.