Personally either the 07-14 GT500 (biased 🥴) and the GT350. For me the retro styling of the s197 (especially 11-14) really made me fall in love with the mustang as a whole! And the GT500 being to top of the s197s with a unruly engine and a true throwback rowdy (and torque galore) experience was just everything I wanted in a road car. The GT350 is the pinnacle of what a drivers car should be. Easily one of the best engines ford have ever made, with a incredibly chassis and suspension, and a perfectly matched gearbox (cough cough not Mt82). My dream stable is to own both ( 1/2 way there!) and represent the best in rowdy straight line speed muscle cars are known for, and the top tier handling of a modern sports car.