The Nak is a nice amp and with a really nice preamp probably going to outclass the Rogue, but with a NAD or Rotel preamp I’d lean back to the Rogue. I personally haven’t heard the PA 5 MKII, but knew the PA 5 well. Nothing wrong with Rogue either, but yes the Nak is going to grab your Infinity’s better. You throw a preamp like a ModWright SWL 9.0 SE on that Nak and it’s another story. The Nak is an easy amp to modify too.
Rogue Sphinx v Nakamichi PA 5 MMKII and a preamp
I am trying to decide between used items for around the same price A Rogue Sphinx V1 with remote verses a Nak PA 5 MK II and maybe an NAD or Rotel preamp with remote. The integrated would be easy but will it sound better then the separates > Both can drive my big old Infinity's but I am guessing the NAK amp will more current