I don't think an M3 or any 911 (except for the GT2's) is a super car.
I just think a Porsche 911 is the next step up in both performance and driving experience. A 911 GT3 or GT3 RS is not a super car IMO but is a serious track machine.
When I think Super car I think Ferrari Enzo, McLaren F1, Bugatti Veyron, 911 GT2RS, Mercedes SLR McLaren and Lamborghini Murcielago....... Cars like that are super cars.
2011 E90 M3 ZCP - Individual Moonstone/Individual Amarone Extended/Individual Piano Black With Inlay:LINK!!!
1994 Euro E36 M3 Sedan - Daytona Violet/Mulberry:LINK!!!