Welcome!
First line of business is to bring car back to "Stage '0' " which is ALL hoses and leads and plugs and dizzy parts , CTS , MAF clean or new , you wont need an OBD reader if you bring car back to as new under the bonnet and then maybe ABS wheel sensors , O2 sensors , cam position sensors , all mounts on engine , etc etc .
Others can comment on a reader if you want one.
I had so many P80 cars i just fixed up all the wear parts and had no proiblems.
Have fun!