Nvram is a great solution but it can have some minor, but solvable issues.
The fit of the stern socket can be quite loose for the nvram and can cause the memory to be occasionally erased due to a loose fit. This has happened on two of my sterns on location.
Technically it's plug and play but if you want it to work perfectly for years, the old socket should be desoldered and the included socket should be installed. This is what I'm doing now.