Ive previously owned a 997.1S, driven a 997.2S and non-S as well as driven a GT3 RS (3.8) and now currently owning an E90 M3. My take would be the 997S and the M3 are similar in 'speed' but are of course totally different driving propositions. GT3 RS of course was in another league!
///M3 | E90 LCI | Space Grey | Fox Red with CF Structure | 6MT | 260M
| My build