Not sure I completely understand the question. The MTX 202 is a 2 channel amp...if you bridge the amp to run a sub you are using both channels to run one speaker...that amp bridged will not handle any lower than 4ohms...so you will "likely" run into all sorts of problems getting your ohms right. Another point is I don't believe the amp will run in bridge mode with all 4 terminals connected. the best way to put it is to recommend that you run no more than 2 speakers on that amp. I have a number of reasons why, but first and foremost is that you DO NOT want to present a full range signal to a sub which is built operate in the lower frequencies only (under 200hz for sure, lower would be recommended). But you do want to present high frequencies to the "mains"...so you have a conflict of interest with the amp right there...as you cannot have both on one amp (unless it has separate channels to do so - ie a 4 channel amp)
specs: # 35 watts x 2 RMS power at 4 ohms # 70 watts x 2 RMS power at 2 ohms # 140 watts RMS bridged into 4 ohms