Need some

Hello, I am looking for some “sound advice” in regards to an upgrade (?) of my equipment. Here is my current system; I am split between digital and analog, I have a Rega P5 with a Shure V15V MR cartridge, and a Marantz SA8004 SACD player. A Hafler DH110 pre-amp into a Hafler DH500 power amp. B&W 804N speakers. My issue is the pre-amp, it has been giving me problems of late, and I feel this is the weak link of my system.
I am looking at the Marantz PM8004 (or 8005) which would replace both my amp and pre-amp, but I am not sure if the decrease in power, 200 to 80 per channel, would still be enough to power my B&W’s. The other option I am exploring is a NAD 165 BEE pre-amp and continue to use my HD500.
Both units cost about the same $1000., which is about my budget, some the main questions I am asking are; am I living on borrowed time with my 30 year old amp (which I assembled, and currently is working perfectly), if I switch to the Marantz integrated, will it be enough power, or is the NAD the better choice.
I am sure there are other choices out there I may have missed, and I look forward to your opinions and input. Thank you all in advance for your help.