I'll always disagree on an original restored being more valuable than a Modified as a blanket statement. There's a whole lot more to factor in. I'd say it's a case by case basis.
A restored base low option car will probably never bring more than a nicely done modified. And the build cost is about the same. Add options and rarity and yes, the original restoration will or should always bring more, but even that has exceptions.
Wanting a Custom fit in an off the rack world.
I don't have time for a job, I just need the money.