Does M&T subwoofer have passive low-pass filter

[jmkcc]

I have a 2009 w/Moon and Tunes. I replaced the head unit and was having problems with hiss. I tried an adjustable line converter, but can not get a good sound with the OEm amp. So I am replacing the amp with a 4 channel that has a pass through. I could not find an affordable 5 channel that would fit under the seat. I am thinking of trying a cheap Boss 2 channel amp to power the subwoofer, but the amp has no high/low filter. Does the OEM M&T subwoofer have a passive filter mounted in the housing? If not, I'm wondering if I can just add a resistor and Capacitor to filter the feed from the amp. I replaced the tweeters and the OEM had a passive filter on them, so perhaps the subwoofer does too.