[Speedracer]

For me, the easiest way to tell an ERA from a Unique is by looking at the roll bar (on 427 cars). The ERA bar is visible in front of the bulkhead behind the seats, while the Unique's is not. Also, the ERA bar's "support bar" is less vertical than the Unique's.

For FIA cars, look where the doors meet the rear fender; on the ERA there is virtually no space between the door and the fender flare, while on the Unique there is a noticeable space there.