If you are comparing these two:
Porsche 996/997/986/987 Rear Toe Link Control Arms – TuneRS Motorsports
Porsche Rear Toe Control Arm Link, 996, 997, 986 & 987
I don't see any difference. The price difference isn't as much as your thread so I may be looking at the wrong ones. Some include bumpsteer adjustment and so at the outboard end they don't have the standard tie rod end ball joint and pin, like this, and these style are more expensive, and not allowed in Spec Boxster (disclaimer: I don't run SPB):
Toe Control Arm (ea), Motorsport Style
These are what I run, and they include the toe locking plate:
Rennline Rear Toe Control Arm W/Bump Steer Kit-Rennline, Inc.
Threaded Mode
