What's different in 2 Moog UCAs @ Rock Auto?

[guy48065]

My (new to me) 04 Limited needs new upper balls. I've read the ball-only sticky but I feel the price difference doesn't justify the extra time & work in pressing out/in the joints so I plan to swap ass'ys. Rock Auto lists 2 Moog UCAs but there are no details on why one costs 2X the other. Advice?

 

[swshawaii]

Moog R-Series (Service Grade)

For the cost-conscious consumer, the new R-Series™ line of control arms is the right choice. With a broad range of applications, and with the quality construction and design you expect from MOOG, R-Series provides technicians the perfect solution for the value-driven repair.

Moog Problem Solver Series (Premium Grade) See page 2

CONTROL ARM BROCHURE
http://www.moogproblemsolver.com/moog/wp-content/uploads/2012/08/ControlArmBrochure.pdf

http://www.moogproblemsolver.com/suspension/control-arms

 

[guy48065]

OK according to Moog they're both the best choice

Visually the extra $47 gets you a zerk. Is that all?

 

[swshawaii]

CK and K Series has upgraded ball joints, bushings, and a limited lifetime warranty. R-Series does NOT have replaceable ball joints.
http://www.moogproducts.com/en-global/Pages/Contact.aspx

https://www.rockauto.com/catalog/x,carcode,1427802,parttype,10401
https://www.rockauto.com/catalog/x,carcode,1427802,parttype,10070

 

[swshawaii]

Click General Description for MOOG Front Control Arm differences. Moog Control Arms: CK, K or RK?

http://www.moog-suspension-parts.com/proddetail.asp?prod=MOOG-K620224#general