Vimberg Speakers

I have always wondered why some speaker manufacturers design their speakers as 4 ohm rather than 8 ohm speakers.  Since 4 ohm require about double the current this limits the kind of amplifier you need to drive them and I would imagine a 4 ohm is less efficient and perhaps they tend to generate more distortion.  Kind of like driving a 600 horsepower car at 65 mph vs driving a 300 horsepower car at the same speed.  Is there an advantage for designing a 4 ohm speaker knowing this.  I wonder if then a 4 ohm speaker provides a more dynamic response.  An 8 ohm speaker would I would think require turning up the volume much less than using 4 ohm speakers.  This also said, I wonder why amplifier and receiver manufacturers do not talk more about current/amperage verses watts when current is actually the most important specification.  Amplifier manufacturers usually try to hide the specifications for amperage numbers because the numbers are lower than watts.  Hope you do not feel this to be a stupid question.  This certainly gives away my being a beginner compared to knowledge and experience this group has.  This said, I have been amazed by the knowledge this group has.  I have also been amazed by the willingness to teach and share their knowledge.

Went online and was surprised they don't even list their specifications.  They look beautiful all except the tweeter and mid range drivers.  They also look like they are made similarly to PSB.  How much do they sell for?