Is there any advantage in having a high flow cat and muffler in either fuel economy or HP?

I have a high flow K&N air and oil filter and my fuel economy indicator on the upper display seems to indicate an increase. also the engine seems to not have to work so hard to get the air it wants.

Thanks

 

you can see marginal gains with a higher flowing intake and exhaust. ive got an intake, 2.5" flowmaster cat back, and 63 mm throttle body. My throttle response is amazing, and it feels like it has a bit more power.

 

where can you find that stuff cheap? rustys has the exhaust package with the cat back and the cherry bomb pro ($150) /flowmaster 40 ($175) /flowmaster 50 ($180). that doesnt really seem like an amazing deal to me since you can get a flowmaster 40 for like $70, unless catbacks are just $100, idk, but ive read all over here rustys has ridiculous shipping too. any suggestions on where to go? maybe summitracing or something???

 

^^^your not gonna find it any cheaper,cat backs for xj's i think are cheap as hell,try buying one for a mustang some are like $450

 

Aero resonator with Aero Muffler = Free flowing exahust + Awesome sound. MPG's went up, very minimal though.

 

Try;

http://www.speedycarparts.com/

I got my all aluminum radiator from them at a great price!!