Visual clues to distinguish a sport would be an M-tech front bumper
a sport rear valence
and ///M trim pieces
As for the cloth/leather interior, all sports came with them but I think were an option on actives and bases. A sure way to get a sport would be be to get a 99 because they only came as sports (but they only imported 656) and came with the 3 spoke steering wheel from the M3.
For a side by side heres a my sport
and my old active
