I'm currently running 95GT front and rear brakes with the matching booster and master cylinder, do I need the cobra master cylinder for the cobra brakes to work correctly?
if you are running 95 GT front and rear brakes then you should be ideally running a 94-95 Gt master cylinder. The 94-95 boosters are virtually the same so no need to booster swap.
Cobra rear calipers are the same as GT rear calipers
If you swap to Cobra front calipers, you need to swapp the MC to the appropriate cobra master cylinder. If you use 94-98 cobra calipers, use a 94-95 15/16" Cobra MC. If you use the later 99-04 cobra calipers, use a 1993 Cobra 1" bore MC
Using cobra calipers with the 94-95 GT will result is a VERY stiff pedal