Question:  I'm not sure which model broadcast band filter to get?

Answer: The M-400x allows use on 80m and higher, blocking everything below (including 160m).  The M-402x blocks below 160m, allowing use of 160m and higher.  However, the M-400x develops a much higher level of attenuation (blocking) of the AM broadcast band.  The M-402x hasn't developed its maximum attenuation of the broadcast band until it gets lower in the AM band.  If the offending stations are high up in the AM band (ie, 1000kHz or higher), consider using the M-423 band pass filter.  This one allows use on 160m and blocks everything above and below, and develops a higher level of attenuation of the upper AM band.

Question:  How do I know if the interference I'm getting is a candidate for the Morgan broadcast band filters?

Answer: Check out this tech bulletin on broadcast band interference.

Question: What if I'm running an amplifier?  They only have a 200w rating.

Answer: Correct, do NOT run on the output side of the amplifier!  DO place the filter between the radio and amp.