Restore faithfully to original condition, or soup it up?
First of all, welcome!  This has been a great place for me to get information I wouldn't find any other way, and I hope it's the same for you.
In keeping with Argenti Apparatus' observation about opinions, I'll try to stick to facts-based considerations.  First, you've already powder-coated the frame.  While that doesn't mean that any vintage value is destroyed, it certainly is diminished.  Second, a quick check showed a few of these for sale, although I'm not sure they're the same year.  Finally, you always have the option to revert to its original state in the future.  So, my suggestions:

Keep any original parts you have.
Build it up with whatever upgrades or customizations you may like.