Up to you on the whole arms. $$$ vs. convenience. Time vs. money.

Honestly, if you have a decent vise, you can avoid the machine shop.

The balljoints knock out easily with a big hammer.

If the bushings give you trouble, you can drill a hole through the face of one bushing, and use a punch to knock the other one out from behind. The second bushing is always easy enough.

I use a big hammer and a pipe fitting to install the balljoints. Helps to put them in the freezer first.

I use a pipe fitting and the vise to install the bushings. Be certain to orient the bushings properly, as specified in the shop manual.

I would have to look, but I believe my special "bushing install tool" is a 2in steel pipe coupler with some of the female threads ground out. I put a steel cap on the other side to give the vice something better to press on. Anyways, just a few dollars at the hardware store.

CA rebuild is quick once you know these tricks.
Best of luck.

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1986 300E 5-Speed 240k mi.