It is a caricature of the ultra-luxury companies Rolls Royce and Bentley. It is stated on Southernsanandreassuperautos.com that the company used to be British and is now owned by a German car company. It could quite possibly be owned either by Übermacht or BF, as Rolls Royce is owned by BMW in real life, and Bentley is owned by Volkswagen, all of which are German car companies.
One of the reasons why Enus is based in both Bentley and Rolls Royce might be due that Bentley Motors Limited is the direct successor of Rolls-Royce Motors. Several Rolls Royce cars, like the Rolls Royce Corniche, were also commercialized as Bentley Continental vehicles, too.