The Series 3 got the wider front end, introduced in 2010 with the Roadster Sport. I also believe that the silencers got slanted ends, but that might be a faulty memory. I don't think the dashboard changed between the S2 & S3. The plastic radiator, so far as I recall, came with the S2 in 2006/7.
The odds are it's an S3, unless it languished with a dealer for a long time. S3 is 240bhp, S2 is 201bhp.
