Lime Rock we are racing on is a real track and it proved quite well in Season 15 - you probably referred to Lime Rock Park Mountain which is a fantasy track.
We used Lime Rock in season 14 but some people thought it was a bit short and difficult to overtake. That's why the Lime Rock version proposed for Season 15 is the Lime Rock Park Mountain version. It should provide a few more overtaking opportunities and a few less lapped drivers.