Replace HDD in Sony HAP Z1ES with an SSD

I've been able to do A/B comparisons with an Aurender N100h (similar in price to the HAPZ1 + mod) and a Melco. The Melco came close, but lacked the last measure of bass articulation and heft. The Aurender has superb timbral accuracy, but blurs a bit in complex passages or highly arpeggiated music, such as Wuorinen Bearbreiten.

You're probably aware of Presto Music, but they have an excellent selection of Hi-def flac downloads at reasonable prices.

Get the Mod and be as happy as you deserve! 

Thank you! 

Thanks for your help. As it turned out, I had the work done by Modwright with their upgrades. I can barely bring myself to turn it off! 

Just say the word.. 

I had to speak to a colleague who's an engineer (I teach Liberal Arts, meaning I'm clueless). He said firmware likely limits the amount of real estate the HAP Z1ES will recognize - though that is a generality, not specific to any particular app. He also mentioned that a NAS (RAID 6/4 disks) can be connected via USB. I have done this, and I can hear no degradation of performance through Audible Illusions m3a Pre/MC 275 VI monoblock/Harbeth 40.1/REL Britannia.
That makes capacity a non-issue - 4 3tb disks in RAID 6 yields 9+ TBs, or about 10,000 cds. If you have more than that, please invite. I'll bring Macallan 18!

Or Lagavulin 16? So much scotch, so little time.

I'm self employed, so my boss is a jerk. He sends me to places like Crudistan on short notice for weeks at a time. Never anywhere like the South of France or Ibiza.

I can tell you that my tastes in music are rather narrow, so my experience is to be taken with a grain of salt.

I think the Modwright upgrade greatly improved the dynamic contrast of music and enhances my experience of large ensemble music; inner detail seems to have exactly the right heft and music like the Poulenc Harpsichord Concerto have astonishing depth. Roxana Panufnik's "A Violin For All Seasons" is breathtaking. I play violin (badly). The timbre and pitch are  very close to the real thing. Subtle arpeggios are clear and distinct. If you listen to complex music, the HAP mod will be a revelation.
If you have specific questions, I'll do my best to answer them. 

I decided to get the Modwright upgrade to my HAP Z1ES, and I had them install the SSD. So, I can't help you. Sorry. I can speak in general terms.
The HDD native to the HAP will look nearly identical to the one you bought.  
HDDs are usually mounted in fitted racks with (I think) four screws on each rail (that is, each side). The screws go through the rail into threaded holes in the HDD case. The drive will have a ganged connector for power and another for the data bus. Unplug these first. Do this only with the HAP powered off AND unplugged. Remove the screws in the rail and the HDD will slide out easily. Note how it was oriented in the anchor rack and orient the SSD the same. Plug in the connectors, being sure they're properly seated, and slide the SSD in the rack until the mounting holes align. You want the screws tight, as vibration will degrade the performance of the drive. 
Again, that's how it works inside a computer; I'm assuming the HAP is the same, but I've never seen the innards of the HAP myself. 
If you live near an audiophile retailer, you may be able to get advice from someone there. Remember, these things are assembled by people working cheap. If they can do it, you can too. 
Sorry I can't be more helpful.