Restore faithfully to original condition, or soup it up? I just got a bargain on a stripped Cannondale road bike frame, and plan to make it simply awesome. (As far as I can tell, it's a 1997 Cannondale R500 or R1000). So far, I've only powder coated the frame to give it a shiny new paint job.
I'd interested in opinions here - Should I restore it as faithfully as possible to the original condition? Or should I improve on it, upgraded gearing, disc brakes, etc.
Which would version would have the higher value, in your opinion?
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.