So what exactly does S197 mean? I know its the numerical representation of the 05+ year mustangs but does the 197 do with anything?

197 chicks per mustang perhaps?

 

The S197, is also referred to as the D2C by FORD. **D class 2 door coupe** This is the platform for the MUSTANG.
A guy named Sid Ramnarace, a Canadian, actually designed the retro 'Stang. He had worked in designing table ware, cutlery, textiles etc before working with FORD.
S197 is the code name for our cars, and the best I can tell, the "S" is for Sid, and the 197, is the 1st 3 digits of the year Sid was born....1973.
That's all I know.

 

IF your right cool, but that sounds like a stretch to me!
But on another note BOY did they do a nice job on our cars! 05SDI

 

I thought the 197 was his weight!