most 'lightly' modded SRT-6's are faster or AS-fast as the following:(taken from google searches of car and driver and road and track; i understand other reviewers sometimes get different results....)

2008 BMW M5 =12.8

2008 Audi RS4 =13.0

Audi R8 =12.8

2008 BMW M3 =12.7

Aston martin DB9 =13.2

Aston martin V8 vantage=13.3

Porsche carrera =12.8

jaguar XKR =12.9

Mercedes SL500 =13.9

Bentley GT =12.8

porsche cayman S =13.2

Mercedes S65amg =12.6

'heavily-modded SRT-6's are close to:
Mercedes SL65 = 11.9

2001 Lamborghini diablo =12.0

please feel free to list any others i have not mentioned......

amazing that our 'affordable' sports cars run so strongly against supercars!!!!