not sure
 

i have a 2003 3.8 ltr convertible i am trying to figure out how to tell the diff. between mach1 gt or the cobra

i guess the answer your lookin for is the badges on the fenders? cobra's have the snake on the fender and grill, mach1 have no grill and say mach1 on the trunklid and the bottom rocker stripe, and gt will say gt on the fender.

are you asking how to look at them and tell the difference or are you asking what the difference in them is?