The 4100 has a highish output impedance (i.e. low damping factor) so you have to keep that in mind when choosing a speaker for it. Today's speakers have a much lower impedance in general and the 4100 will not like that.
I would suggest the JM Lab Chorus 714 which is a small floorstander. If you really want montiors, the Chorus 707s is also quite good. These JM Lab speakers will compliment the mellowness of the 4100 really nicely IMO and they have friendly impedance and sensitivity.
I see you have Thiels in your other system so I am rather sure you will like the JM Labs. Nice little setup by the way - I used to own a C712 and it was great for the money. Arthur
I would suggest the JM Lab Chorus 714 which is a small floorstander. If you really want montiors, the Chorus 707s is also quite good. These JM Lab speakers will compliment the mellowness of the 4100 really nicely IMO and they have friendly impedance and sensitivity.
I see you have Thiels in your other system so I am rather sure you will like the JM Labs. Nice little setup by the way - I used to own a C712 and it was great for the money. Arthur