You can use any of the VPN types which will allow you to tunnel layer 2 over it. However my experience in doing so was not satisfactory for Tally. What hardware / software are at the end points in these locations ?
Opnsense will run fine on x86 thin client like HP T620 as long as you dont enable IDS and such. I had Opnsense on T620 for a long time with dual WAN. As the processor is weak, you will need to be patient with upgrades and loading of blocklists on bootup etc though
I use refind as my bootloader which can boot multiple OS. As long as the OS installer puts its boot files in the EFI partition there is no issue.You dont need to depend on the OS specific bootloader at all. I would have atleast 4 or 5 distributions installed in my system and refind has no issues...
Sorry, not HDR. In Google Home settings for Chromecast Audio, there is a setting to enable Full Dynamic Range. If this is not turned on, do try that and see if it makes any difference
Audio quality is very subjective, what sounds as excellent for one person might be below average for somebody else. Listen to the stock audio system for some time and see if it really needs improvement. High end car audio systems are expensive and difficult to setup unless you get a competent...
No difference. Select the one which seems easiest. These kind of PCBs will have very thin tracks, so when soldering be careful not to overheat or the tracks will lift off and it will be a mess
You can disconnect the wires from the input side and connect it directly to the speakers side matching the colors. If disconnecting the wires is difficult, short the points b and c and also a and d with a short piece of wire / jumper
The first post said you were considering upgrade of DAC. I have been through few upgrade cycles, which taught me a few things. Shared them thinking that it might be useful for making the right decisions
I have 3 entry level DACs other than Chromecast audio and there is no night and day...