I suspect if you looked at the manufacturers 'numbers' the VAST majority of ERA's are ordered with the basic 'street' body with every intention of then building an SC style car. Seems to me the actual SC body from ERA cost more than the 'street' version body, perhaps that is a factor. Very few ERA's actually end up being built as true 'street' body style cars.
The differences are subtle, but become clearer when you know what to look for. SC will have the tach where the speedo is on street cars. No glove box on SC and different fender flairs. Worht the extra cost? Tough call. I swapped out the location of my tach and speedo to get a more accurate dash layout myself, not an easy thing to do by the way.
Bear in mind that SPF's parent company is "High Tech" (I think thats how it's spelled) and is NOT affliated with the OLD or NEW "Hi Tech" replicas. Two (three?) separate companies (like this aint confusing enough all ready).