Is your H3 leased or owned? If leased it would not be wise to be opening it up and swapping out hardware. Having said that my first instinct is to say no. That's what adding external HDs for extra storage accomplishes.
2 hopper 3's and your running out of space. Perhaps maybe be a bit more selective with your recordings. How are your hopper 3's hooked up how bout some install pics a year later and dollars short.
I don't believe you can replace a Hopper internal HDD. I don't think it will initialize it on its own.
The Seagate ST2000VM003 are only $43 now on Amazon so ordered a spare.Sure it will; I replaced both of my HWS internal HDD's with brand new ones when they both crashed last year, got the HDD's off Amazon.
HOWEVER, I DID use the same, exact replacement HDD's as what was already in them...so I was not trying to put a larger one in that what was already in there.