I've been running the CAP arms on my Challenger for well over a year now without problems so far. I didn't know of any issues at the time I bought them. This isn't the first time that I've heard about failures of CAP parts, but with the internet the story/evidence isn't always clear cut. It's COMPLETELY obvious based on those pictures that this was a weld failure though, and I'd have to say I'll be looking for a new pair of tubular UCA's.
And as Joe said, there's nothing wrong with tubular a-arms in general. They are used in everything from F1 cars to Baja racers, and in the case of F1, on cars that cost over 3 million dollars. Like anything aftermarket, there are different levels of quality. CAP has proven itself to be low quality at best. And unlike a lot of things, the CAP arms are not cheaper than the alternatives!
RMS, Magnumforce, Hotchkiss, Firm Feel and Just Suspension all have tubular arms that are quality pieces that I would run well before I ever went back to stock design UCA's.
For those of you that think you're safe running ancient stock UCA's instead of tubular ones, I suggest you think again. Stock UCA's flex, twist, and eventually crack. And unless you're the original owner, you have no idea how many curbs, potholes, or accidents those UCA's have seen over the last 40 years. Also, the factory UCA's were designed around the original tire/rubber compounds available at the time. Needless to say, the tires that originally came on our cars are closer to hockey pucks than they are to modern tire compounds. More grip at the tire equals more force transmitted to the chassis, and in the case of the stock stamped arms, more flex.
