"Servicing, Assembling and Adjusting" vs "Carrera Turbo Service Information" 1984
 

I'm looking to pickup some factory manuals for my 1984 Targa. I see the two books below on eBay, what is the difference?

I know these are not the full factory shop manuals...what are they?

What other manuals/books did Porsche produce specific to the 1984 model year?

What is the best source of an accurate wiring diagram for my 1984?

"Servicing, Assembling and Adjusting" WKD 490 421

"Carrera / Turbo Service Information Model 84" WKD 490 221

https://i.ebayimg.com/images/g/WHYAA...Bv/s-l1600.jpg

https://i.ebayimg.com/images/g/W00AA...Ob/s-l1600.jpg

The "Service Information" booklet has the factory wiring diagram, but descriptions are in German. This booklet is more of a general how things work explanation booklet. The "Servicing ..." booklet is a how to booklet - how to replace the air filter, brakes, etc.

The service info booklets were issued to the mechanics at school for training. And then available for purchase. They contain all the changes from the last model year. The 84 booklet is huge as major changes were made to the Carrera. The other booklet is for service and adjusting.

84 wiring diagrams are in the 911 84-89 Porsche Workshop Manual.
A scanned copy of this manual is available as pdf. All diagrams are in English.

Quite a big file or nearly 150 MB.
If you want it just let me know and I'll wetransfer it.