It's not all about port noise.. If it was JUST noise, big ******* deal, 140db of bass and the trunk muffle that anyways. The MAIN issue is that even before a port chuffs it "compresses" and when it's chuffing its REALLY compressing. Basically realize what you see in WINISD is a 1w/1m response. It's the acoustic combination of your port and your woofer. Woofer does the higher notes, port plays notes near tuning, they both play stuff just above tuning, and below tuning they play stuff together as well, but out of phase.. However, a smaller port has a lower potential for moving air than a bigger one.. So when the port compresses all your notes near tuning will stop getting louder while the woofer keeps going.. So once you turn up the volume knob that nice low end the program shows you goes away as the port compresses.. Imagine a response much closer to sealed box, but even higher distortion due to the air noises and turbulence. So yes, it's a mess.. Will it sound terible, hard to say, turn it up and see what you think..
I would still strongly suggest finishing it for now, run it for the time being, but build a new box with the guidance I and SQ have given you.. I think you'll find the A/B comparison enlightening.
