I've owned an ARC 100.2 so I can speak on that amp. Owned a B&K ST 140 and although a different amp than you mentioned it was a nice amp; great little amp for the money. Never owned the Parasound A21 but have listened to it at one of my favorite shops and it's a really nice amp, but it's not a ARC 100.2. Funny I mentioned my B&K amp because I gave it to the owner of the store I mentioned and they used it on the floor for months and one of the salesperson stated he preferred it over the A23 on Magnepan 1.7i's; not sure I'd go there but it did sound very nice on the Maggie's.
I ended up selling my 100.2 only because it just didn't have the juice to power my Aerial Acoustics to where I knew they could go and I ended up with a much bigger amp that works much better. The 100.2 is a great amp with a little tube magic. It's not too soft mind you but if you want a cold, sterile amp it is not it. The bass is really good on it as well and it holds it own against much bigger amps there as well. It's a great amp and no way would I take a Parasound A23 over it. Only reason I'd maybe consider the A21 is if the 100.2 just doesn't have enough juice for your speakers. If speakers are not a concern the 100.2 is the better amp. The A21 is a really nice amp but it's not magic. I'll admit I prefer my Pass over my previous 100.2, but I still miss the 100.2. Could listen to that amp for hours and get lost; no fatigue at all.
Our Parasound dealer is a Monitor Audio dealer. Your Silver 8's will be no problem for the 100.2 and you don't need the power of the A21 in my opinion. You could easily drive your speakers with an A23 as well but the A21 is better than its little brother. Monitor Audio's can't play to insane levels so I don't think the A21 will play any louder than 100.2 on your speakers. I'd for sure do the ARC 100.2... it's the better amp.
I ended up selling my 100.2 only because it just didn't have the juice to power my Aerial Acoustics to where I knew they could go and I ended up with a much bigger amp that works much better. The 100.2 is a great amp with a little tube magic. It's not too soft mind you but if you want a cold, sterile amp it is not it. The bass is really good on it as well and it holds it own against much bigger amps there as well. It's a great amp and no way would I take a Parasound A23 over it. Only reason I'd maybe consider the A21 is if the 100.2 just doesn't have enough juice for your speakers. If speakers are not a concern the 100.2 is the better amp. The A21 is a really nice amp but it's not magic. I'll admit I prefer my Pass over my previous 100.2, but I still miss the 100.2. Could listen to that amp for hours and get lost; no fatigue at all.
Our Parasound dealer is a Monitor Audio dealer. Your Silver 8's will be no problem for the 100.2 and you don't need the power of the A21 in my opinion. You could easily drive your speakers with an A23 as well but the A21 is better than its little brother. Monitor Audio's can't play to insane levels so I don't think the A21 will play any louder than 100.2 on your speakers. I'd for sure do the ARC 100.2... it's the better amp.