03-04 Mach 1's will be in the low 5 second range for zero to 60 times and mid to lower 13's for the 1/4 mile with an average driver. With some practice a friend of mine has been able to get his down to 13.1 seconds in the quarter on stock tires. Add some stickies and you know you'll be lower. The strength of the Mach's come with the power band of the 4 valve 281 cu in engine. A lot of people mistakenly think they are just left over 2001 Cobra engines but they are not. They are completely reworked. And once you reach 80+ mph the shaker really does take an effect.
As for the 2002 bugeye you have a 1/4 (unmodded) of somewhere in the mid 14's. There is a difference of about 300 lbs between the two vehicles and you do have the benefit of the tenacious grip of the AWD but you're going to have to turn up the wick somewhere on your amount of boost and really work on the top end to keep up with the Stang. I'm by no means a Subie expert so I don't know the best way you can do this but I can tell you the about the Mach and that you will most likely have to do some serious mods to pace one.
Hope this helps!