I went 55-57 Chevy crazy when I moved to South Carolina from upstate New York in '77.
The move from the land of rusted out junkers to almost rust free cars got me hooked. Leaving dirt track racing behind, I invested that previously wasted money on collector cars. Over the years I bought and sold probably close to 75-80 of these cars. Most of the good ones finding new owners in the rust belt states.
Along the way I bought a bunch of NOS parts and accessories, much of that I still have.
I switched gears here about 15+ years ago and transferred over to '48 and earlier Fords. Only old Chevy I have is my '55 Bel-Air 2-dr that I bought Oct '77. It was our honeymoon car and has been sitting in the shop corner since '85.
What rare pieces have you collected? I have a rare pair of NOS rear bumper guard that were required on '57s sold in the state of Vermont. Story goes that Vermont didn't like the single light bulb the '57's had to illuminate the license plate. Chevy took the standard rear guards and put lights in them, similar to '55-'56. This addition satisfied the state of Vermont lighting requirements. And, these aren't the short wagon guards.
The most expensive option I have for a '57 is a complete factory 283 hp fuelie unit, as removed from a running car, probably 40+ years ago. Includes the distributor, passcar air filter and fuel filter. Years ago I was going to build a 150 black widow, but a guy came around and wanted the car I was going to build real bad.
I still have a complete NOS front bumper. Another item I have, that I thought they'd never repop, are the Fenton dual outlet exhaust manifolds. A new pair is now about $300. Less than what I paid for my original pair back in '88!!!!! I saw the originals going for as much as $2,000+. That invest took a Wall Street noise dive!!
So, I share with what you're doing. I don't look at buying these parts as an obsession, I look at it more like an investment (Fenton manifolds excluded!!).