Likely if you're talking about more modern ones like the HR S5902, not sure what the S8009 is.
JVC often shared the main video and system ICs in the consumer SVHS and Hi-Fi models from the same lineup, with the SVHS and functions TBC on add-on boards (the "pro" ones like the SR V101 may have been a bit more different). The playback of the non-TBC versions of a SVHS deck should be pretty close to the more expensive one, sans the TBC. Some of the difference between models also was about editing features, like edit control connectors and flying erase heads, which doesn't impact playback. For some of the later ones they sold, the
internals seem to be the same as some Toshiba units, not sure who made them.
The mechanisms seem to have been mostly the same as well between the cheaper and more expensive ones from the same lineups. One difference I have seen is that seems to be that the cheaper ones seems to have dropped the tape stabilizer thing, and the dynamic drum systems is of course reserved for some specific models.
To what extent the video heads differ between models and whether the high-end ones had more precisely made and aligned ones I don't know, haven't been able to find much info about that.
This manual:
JVC-HR-S9500-Trn.pdf (found
here but attached for posterity), includes a list of what models use which video IC for the 1998 lineup and shows a bit what's shared between models. SVHS models and some 4-head hifi ones use a JCP-8016 IC, while the 2-head and some 4-head ones use a hitachi chip instead. It also mentions 2 different syscon ICs being used, though not which models uses which ones.
For another example,
this service manual for the S7800 refers to the S4800 for parts other than the 3D digital module (which contains the TBC) and a tuner demodulator, or the SR-MV30US
here referring to the non-SVHS schematics other than the 3D digital/SVHS board.
