5" is overkill. It does sound different. My truck is at 700hp at the rear and I have a 4" down pipe (aftermarket turbo), hollowed out cat, muffler delete and mega cab resonator.
If it were me I would get a nice drop in reusable non oil air filter....
70 Challenger 1960 Town Wagon P Pump 24v cummins project 06 Mega 3500 Drw 2wd 12 Durango R/T 18 Power Wagon 67 A100