The best coupling caps in power amp ?? Mundorf, Infinicap ??

Mundorf are excellent caps.  M-cap supreme, great in midrange, very rounded sound.  The silver has better clarity, more tranparent.  The infini-caps are neutral, kind of forward sounding.  Very analytical sounding caps, nothing really interesting about it.   Go with Mundorf caps, you will be happy with it. 

I placed Jupiter copper foil caps in my 300b SET (replacing the stock Solens) and it's a worthwhile upgrade.  I went with them rather than the Duelund CAST due to the lower cost and enthusiastic recommendations. 

The Duelund CAST is superb in my DAC  and speaker  crossover (tweeter).  Though expensive I believe they are definitely worth their cost. 
Charles 

I would agree with your assessment of the Infini-caps, but I have some interest in maybe using Mundorfs.....I think I will read on about other experiences

Two very experienced modifiers on this site Grannyring and salectric seen to prefer the Jupiter copper foil compared with the Mundorfs. 
Charles