This upgrade has turned a HT amp that I would get bored with listening to music, into an amp with detail space and punch that I have only ever had from my VTL tube amp. The VTL is still better but I would expect that from an amplifier that cost $3800 in 1993, although having said that I haven’t wanted to turn on the VTL recently as it generates a lot of heat in summer. The Marantz has become a HT amp that you really couldn’t buy.Total cost of second hand SR 8500 included mod NZ$650 plus about 1hr labour, easiest mod I ever did