a pretty dumb question
 

Is there a length difference in exhaust piping length between hatch/coupe/sedan?

Sedan + coupe = the same.
hatch is slightly shorter after the mid-pipe (exhaust tip)

Ok. So basically the mid pipe is the same.. but where the catback bolts to mid pipe is the shorter part?

Yup I put a 4dr cat back on my coupe. Then on to my hatch just had to shorten it about 4 inches. Axle back is longer in coupes 4dr...