High-End Caliburn Build Advice

I’m trying to build a Caliburn 4 with as high FPS, accuracy, and quality possible, that’s still fun to actually use.

I don’t own a 3d printer, but I am mechanically minded, and thus perfectly fine with assembling the gun myself. I’m planning on using half-lengths darts to mainly go plinking with it, but still play in a few nerf wars that allow a Caliburn 4.

Money is no object this time around, and I have a few questions before I bite the bullet (excuse the pun) and buy the parts to build one.

1. Who should I buy the 3d printed parts from?
2. What upgrades should I purchase? (ie aluminum ramrod, longer barrel)
3. Who should I buy my SCAR/BCAR from?
4. With the previous questions in mind, what spring(s) can I reasonably use? (No two handed priming)

I love Nerf and I hope this post will help me and others in building their ideal Caliburn 4!