97 XJ cat flow better than a 90 MJ's?

here's the situation, i got a 97 parts XJ that had a newer exhaust on it. i'm wondering how much i stand to gain if i were to swap the front pipe/catalytic converter onto my 90 MJ 4.0L. the front pipe looks to be much larger with smoother bends and no crimps in the corners like the MJ's. the cat doesn't look much different, but the MJ still has the original cat with 151,000 mi. thanks