But if you take the trouble to run the earth back to the battery, you will take all the existing 20+ year old connection points, every one of which builds up a high resistance, as was the original idea behind the rewire of the live, mental not doing so, esp when you have to lay the live down anyway.
You don't need the incorrectly labelled relay pictured, a std single pole switching relay is fine, doesn't need to be a changeover like the piccie shows, and incorrectly labels as a single pole double throw.
As for suspension a good road set up is Koni adjustables on hardest setting, with std ride height avo springs, I've used both ahmed and avo std ride height and prefer the avo, but I'm on coilys anyway now.
Before spending money on bushes etc I'd ensure the engine is healthy, and do a complete service regardless of what any service history shows, a belt costs around £60 or so for a new one, and is a lot cheaper than a head/valve rebuild, then the rewires, fuel filter change as well as oil/filter, plugs etc.
The kits from deflex/flow flex etc as a kit on ebay are ok and work fine, but I'd use the group a strut top bushings, as some poly are two piece and horrible, change the rear diff mount as this was seriously crap to start with let alone 20+ years old and saggy.
tabetha