I started collecting Darda Cars around 1994 after diging through my parents stuff from when I was a kid. I at the time realized how much I loved and missed Darda Cars my favorite toy from childhood. I was then hooked, I started frequenting second hand toy shops and some local toy shows, even a few garage sales (I never found any Dardas at garage sales though) to find more cars.
I was able to acquire some of the last Dardas that could be found around my area in second hand toy shops as they became harder to find as my generation of sons grew up and parents sold off their toys. As most of the supply of Dardas that my generation acquired was sold off and no longer around to be found.
Ebay then came along and I was able to build my collection up (from about 2001 on) through ebay and trading cars with Karl in Germany.
As Darda Cars were always a more upperclass high end toy only carried in fancy toy shops, eventually mostly high end local toy shops disappeared in the US as Toys R Us became esentially the only toy store around. There aren't as many Darda Cars around in America. Dardas were never as prevailant a toy as was in Germany, there aren't as many collectors as in germany and not nearly as many varities of cars to collect. A Retro movement popped up in Germany around 2000-2005 that had a lot of middle aged men wanting to regain memories of their youth, so Dardas had a surge in popularity and collecting.
I love Darda Cars! I conisider myself a little bit artist, and a little bit engineer. I love how the car designs have to be conformed to the generic chasis and fancy winding motor (most wind up cars have a cheap winding motors) that makes darda cars what they are. There also isn't a billion of them like Hot Wheels so they are much more rare; your collection doesn't have to blow up out of control like some Hot Wheel collections.
Some of my favorite Car designs: Stratos, Mercedes 190E, also the Mercedes Garbage Truck, Dumptruck, and Firetruck are very unique toys.
All are artistic interpretations of the car designs that have to be well designed to look good to conform to the chasis dimensions and wheel base.