For now, on my '99 SE, I replaced the resonator with a straight pipe (not a glasspack) and the stock Ford muffler with a Ravin'. I do not have the drone problem many have complained about. The only negative being that until the system heats up, I do hear a "4 cylinder, high pitched" whine at 3000 rpm and 4500 rpm. Again, when the engine is cool, at full throttle this sound occurs all the way to redline. But, fortunately, this obnoxious noise disappears completely when the engine and exhaust are at operating temperature.
Eventually I'll add a second Ravin' with a custom cat-back system. I'm pleased with the sound and can detect (seat of the pants!!) an increase in hp and torque.
FYI>>>>>>>I have a K&N drop-in air filter and
experimented with removing the air box completely, and with leaving the entire air delivery system intact. While at high rpm's I cannot notice any major power difference, at low rpm's I can feel (again, seat of the pants!!!!!!) a power increase by leaving the stock air box unit connected. Without the airbox, the filter apparently sucks in too much warm air from the engine, decreasing power. Now, I'll have to experiment using additional ducting to the airbox to see if there is any additional power to be gained.
Nathan
