I use the NAD M3 with the Polk Lsi15s with complete satisfaction. Prior to that I used the same speakers with the NAD C372 with complete satisfaction.
I'm my opinion your best option is the NAD C375, which is the upgrade to the C372. Save your money. The M3 although a good upgrade may not be worth the extra money over the C375. Plus the M3 display seems to have a problem with fading out.
Using either amp with the Polk Lsi9s would be a no brainer for me.
The only reason I put the M3 in this system is due to upgrading from this amp in another system.
I'm my opinion your best option is the NAD C375, which is the upgrade to the C372. Save your money. The M3 although a good upgrade may not be worth the extra money over the C375. Plus the M3 display seems to have a problem with fading out.
Using either amp with the Polk Lsi9s would be a no brainer for me.
The only reason I put the M3 in this system is due to upgrading from this amp in another system.