The 05+ Mustangs can get really good steering angle, my boy Dave Jones can get crazy angle and all he's done is remove his steering angle limiters. I removed my steering angle limiters but I don't have S197 angle
The steering angle limiters is a free modification that any Mustang can do, just pull back your tie-rod boot, steer to lock, pull out the plastic clip that's there, replace boot, turn all the way to the other side, repeat process for other side.
It took me 5 mins to do it and I'm no where NEAR good at mechanics (for those who remember my timing belt fiasco).
But yeah, SN-95 and below (04 on down) Mustangs aren't very good with the angle, but S197 (05+) are really REALLY good.
Although . . .I removed my steering angle limiters and I've been able to get DEEP when I get my grip to the rear wheels!
-Dave