I got a Quatro 4 on Saturday from the original owner. When he bought it in 2013, he had the factory replace the push pull pot with a switch, and had the 53/10 pickups replaced with M pickups. My understanding is these were intended for heavier styles of music, although they sound pretty good so far. I have the original 53/10's in the case, so was wondering what differences I'll hear if I switch them back. I play mostly blues and "classic" rock - more overdrive than distortion. I can get a great sound from the M's, and my usual philosophy is to stop there, and not overthink it, but given that I've never even heard the 53/10's, I'm just wondering what I could expect - thought I'd ask others who are familiar before doing the switch. Thanks.