A dry sump and an external
oil pump are not the same thing.
An external
oil pump should be at least as reliable as an in-block
oil pump.
Because the external oil pump is belt driven there is the need to make sure the belt is in good condition and replace it periodically - on a race car the belt is replaced once a year whether it needs it or not.
Performance should be the same - although most have some sort of adjustablilty.
As far as overkill on the dry sump - a Cobra is already in that category, isn't it?