auchencrow is right.

In general, almost every "modernization" attempt has some aspect that becomes a defining point in the rebuild.
At that point, you have to decide whether to go all out or simply accept some limitations. That point depends on budget, ability, and risk aversion.

It could be an appearance issue, functionality, or simply an offense to sensibilities, but it's usually something.

My hat is off to the folks who can patiently wait for and/or make things happen with the OEM or very close to OEM parts.
They get a bike that generally rides like the original, looks like the original, and keeps the intention close to the original builder's target.

It really depends on what you want.