I've used Mundorf Supreme S/Os as couplers in a couple pieces of equipment. Altho I'm no GEA who can hear all kinds of subtle differences, I found the MSS/Os to be rather clean and detailed (but never edgy) yet a tad warm sounding. You may well love their sound.
That said, I now use Cardas Golden Ratio as my 'affordable' cap and SoniCap Platinum as my best-money-can-buy cap. The CGRs are more tonally neutral than the MSS/O while not losing any of music's harmonic richness. The SPs are even cleaner and quicker than the CGRs. Since you need only 2 caps, do consider the SCPs. If you need a large value, say, more than a couple microFarads, you might consider a large CGR bypassed with a SCP.
http://www.soniccraft.com/products/capacitors/film.htm
.
That said, I now use Cardas Golden Ratio as my 'affordable' cap and SoniCap Platinum as my best-money-can-buy cap. The CGRs are more tonally neutral than the MSS/O while not losing any of music's harmonic richness. The SPs are even cleaner and quicker than the CGRs. Since you need only 2 caps, do consider the SCPs. If you need a large value, say, more than a couple microFarads, you might consider a large CGR bypassed with a SCP.
http://www.soniccraft.com/products/capacitors/film.htm
.