Marantz sa11 S2 - upgrade to outboard DAC?

I was just wondering if this unit is worth installing an outboard DAC?  If so, what would be appropriate to look at?  I do not know that much about digital so any help would be appreciated.
What don't you like about the Sa 11- S2? Fairly well respected unit that plays cd's & SACD's very nicely. 
it is nice.  just was wondering if there are any upgrades that would make it even better.
I have the SA15S2b SACD player and some friend brought over a couple of DACs and I even tried a Schiit Bifrost (a step down?) and it always seemed like a sideways move, at best. 

Going with a better PC (TWL Digital American), better fuses (no need to overspend as there are 4) and upgrading speaker cables (Cabledyne Virtuoso) and eventually getting a better integrated (Kinki EX-M1) made it very clear that the Marantz was outputting great digital all along. All that was needed was for the rest of my system to catch up. 👍

All the best,
+1, Nonoise.

I also own SA-11s2 and absolutely love its warm musical sound. I have not tempered with stock fuses just yet. But I am definitely tempted to try an external clock before I mess with aftermarket fuses.

I own a pretty decent DAC but never felt the need to try it with Marantz but I am only using this player to spin SACD’s 😉
Stereophile measurements shows it is excellent for CD playback, except maybe Filter 3 as it has high IMD.
The SPDIF output for SA-11S2 only works for 44.1kHz 16-bit CD.  No output when playing SACD.

New stand-alone DACs support high res PCM and DSD.  You will need another digital audio transport/renderer to make full use of a new stand-alone DAC.

If your budget permits, please consider Marantz SA-10 instead.  It will allow you to enjoy high res playback as well.
i guess i will keep what i have as is.
I have a Modwright Marantz SA8005 and have made some tweeks along the way to improve things. As previous posters have mentioned, fuses are a great start and relatively inexpensive. My Marantz has hard wired fuses but the Modwright PS made a nice improvement with the Synergistic Blue Fuses. Also the ECT's do a nice job of lowering the noise floor and getting rid of hash in the system. The nice thing about Synergistic Research, if you don't like it send it back for a full refund.Good luck