$1000 on a CDP upgrade, suggestions please.

Moving on from a Denon 2900, which replaced an expensive 2 box front end a couple of years back as I wanted to explore SACD. Still like that format but want to get better sound, and I don't care to spend tons to find it. Here's what I've narrowed down as options and I'd be interested in hearing others' views.

1) Get a new Marantz 8001 and enjoy one box convenience, sound close to the best according to some reviews, with some cash left over to upgrade the power cord. Retire the Denon to the theatre or bedroom (or sell it)

2) Send the Denon off to an upgrader such as Underwood and have it modded to improve the sound. Stick with the player I know and squeeze an improvement out of it for a few more years until another generation player raises the bar.

3) Buy an external DAC (e.g., PS audio or Benchmark), improve the redbook but keep the option of SACD.

I prefer the one-box solution if only for neatness and generally subscribe to the view that a new decent player every couple of years is a better investment than splurging thousands on today's greatest digital design but then, I don't get out much so maybe I am missing the truth and it's worth just spending more. If you have tried any of the above options, I'd be happy to learn from your experiences.