I had a major hassle getting a "like for like" car. The 370 is in the same 'category' as a BMW 320d or some such guff, so I politely ranted at the hire company till they agreed to give me a Porsche, they let me down so we switched to another hire company and eventually got the Boxster 2.7 PDK. A diesel taxi as like for like?!
So: if they offer you something rubbish, ask them about the way they group the cars because they don't have one of every car in the fleet, and explain that you were promised a like for like meaning you understand you'll be getting a two seat, RWD sports car not a taxi