I cannot for the life of me understand why a player in pursuit of twang would choose a C Rex speaker. They seem to be very popular lately, but the entire purpose of that speaker was to cut some high end to suit all the players complaining their Tele had ice pick tone. I put one in an amp that has no tone control and is too bright, and it did help dull the tone a little. I don't like the whole dulling function though, and prefer to have sweet but bright tone rather than dulled highs. Not familiar with the Bill M mods but I'd agree the BJr isn't a twang amp, and a PRRI might be twangier. Just not with a C Rex if twang is your goal. You can still make it twang but the C Rex most certainly dulls the tone. This is not based on playing an amp with a C Rex though, it is based on running one amp through a C Rex and then through other speakers. If you just play a basic twangy amp with a C Rex in it, and don't then run that amp through a speaker that doesn't dull the highs, you might not realize how much that hemp cone dulls tone. I mean it's a fine speaker for players who complain of too much treble. Wrong choice for players who complain of not enough twang though.