2003 Ford Expedition budget performance exhaust

Purchased this 2003 Ford Expedition 4x4 EB edition a few days ago. First thing I always do on a vehicle is get the intake and exhaust improved flow. The exhaust is fairly simple and budget, cut the old 40 pound boat anchor muffler, install light weight free flowing muffler, add a nice looking tip to back up that great new sound and done deal. This budget exhaust mod was cheap and will pay money back with improved fuel economy, low end torque as well as power increases. Of course more go from less pedal than before. The muffler single chamber inline 2 1/2 IN/OUT round muffler was only $25 on ebay, the exhaust tip only cost $12. Having the muffler cut off and new one welded on as well as exhaust tip was $70 at a local exhaust shop. $107 budget cat back exhaust system which saves hundreds compared to just buying an entire cat back exhaust system which is not necessary. The only bottle necks on a stock exhaust system is the factory muffler and catalytic converters. Eventually I will replace the 4 factory catalytic converters with 2 magnaflow increased flow converters. Ford for some reason put 4 converters on and only two are required since the cat sensors are behind the first converter and no sensors behind the second converter basically telling me they are not needed to pass the sensor test.