[A Cobra guy]

Jim,
I have a soft top for my E-M. My side mirrors are mounted out on the front fenders. My answer to you would be yes, the mirrors help. My left side actually has a bad blind spot with the mirrors out there on the fenders. With no top a quick twist of the head checks that spot. With the top up I can NOT see that spot.

Yes, put the mirror on. the more you can see the better. For me it's more important to keep my Cobra in one piece than the way it would look without that mirror there.

Harvey R.