[FransB85]

it's hard to say up or down on this -grade business. supposedly, these control arms allow a bit more flex than the aluminium ones. However, I think under normal driving circumstances this difference resides between the ears of the beholder, so to speak.

The reason to switch over to these is a cost issue (though some racers like to seam weld these babies, which makes them just as stiff and more durable than alu). If you have damaged your alu control arm beyond repair, you can easily swap the alu ones out for a brand new pair of these vw-based (thus common and cheap) control arms for less than the price of a single aluminium control arm.

If it is only about the ball joints, you can just order a rebuild kit for your control arms, for even less money. The condition is that the ball has not eaten into the aluminium, since this is a pretty unfair match in favour of the hardened steel ball, rendering your arm useless/non-rebuildable.

I have performed this rebuild myself recently and it has been one of the more satisfying projects. I would suggest replacing both at the same time (save one alignment, peace of mind, etc) since you get a set of two anyway.

The set sold on the internet contains ball joint bearings/cups of a superior bronze-alloy that supposedly last the lifetime of the car (YMMV) as well as all the other hardware, as you have no doubt seen already.

So have a look at the ball joint housing and choose.

PS, this is also a good time to replace bushes/caster blocks if they have no been renewed.