WindowDude

This system sounds absolutely incredible but I'd like more bass.

Anyone have any clue on what parameters I need to stick to if I want to swap out the sub speaker?? Ohms n what not. I'd like to just utilize the factory amp. Looks like it's an 8 inch but I'm going to try to get a 10 inch in there. Any help would be awesome! Crutchfield couldn't give me an answer

PeterA

i think It should generally be ok but I would try to match the impedance rating of the speaker represented in Ohms, usually 2 to 8 Ohms. Lower Ohm ratings put more of a strain on the amplifier.The manufacturer may have matched the speaker to the amplifier. Higher impedance ratings generally have lower sound output which you could always adjust. I don't know the speaker they use in ML but it could be a high quality speaker that may not be be improved with a larger cone. the bass output.
The other comment I want to add is that bass output from the speaker is strongly determined by the enclosure and the "tuning" of the speaker surround to the speaker to have a good frequency curve. This is critical for the lower frequencies. You are going to change that dynamic, unless you are talking about buying a speaker that has its own enclosure.

LexRuger

It would be a lot easier and sound better to add a separate sub. You're not going to get a big improvement in bass with a free air sub and the stock amps power.