I agree that most 4 cylinders just don't have that nice, heart-warming sound of a well-done exhaust on a V8. I have heard some, however (particularly the WRX), that do sound pretty good.
On my old Hyundai, I removed the lower intake resonator and taped over the hole. It didn't make the intake any louder, but it got rid of a little of the annoying resonance at 3k - 4k.
I tried removing the whole intake snorkel at one point, so the airbox would draw in hot air from the engine bay, but I didn't keep it like that long enough to get an idea of mpg (put it back after about 1/2 tank of gas). MPG seemed worse though, based on how fast the gas gauge was falling. Unless I was driving at sustained speeds above 40, the intake air got so hot that the ECU was maxed out on the timing retard (due to IAT sensor, no knock sensor). With 87 octane in there, I couldn't break 3000 - 3500 without pinging (air too hot, couldn't retard timing enough), so I had to put it back on before I could even try to get on the highway.
Personally, I think my Jeep has one of the best sounding stock exhausts I've heard. Mine is slightly louder than other identical Jeeps I've heard (but same sound) due to the cat starting to fail. I think some of the media has just blown out. It'll get a full new exhaust with new cat, etc. in the spring/summer. One of my friends took video clip of it last week:
On my old Hyundai, I removed the lower intake resonator and taped over the hole. It didn't make the intake any louder, but it got rid of a little of the annoying resonance at 3k - 4k.
I tried removing the whole intake snorkel at one point, so the airbox would draw in hot air from the engine bay, but I didn't keep it like that long enough to get an idea of mpg (put it back after about 1/2 tank of gas). MPG seemed worse though, based on how fast the gas gauge was falling. Unless I was driving at sustained speeds above 40, the intake air got so hot that the ECU was maxed out on the timing retard (due to IAT sensor, no knock sensor). With 87 octane in there, I couldn't break 3000 - 3500 without pinging (air too hot, couldn't retard timing enough), so I had to put it back on before I could even try to get on the highway.
Personally, I think my Jeep has one of the best sounding stock exhausts I've heard. Mine is slightly louder than other identical Jeeps I've heard (but same sound) due to the cat starting to fail. I think some of the media has just blown out. It'll get a full new exhaust with new cat, etc. in the spring/summer. One of my friends took video clip of it last week: