Corroded electrics,possible to clean/solder?
 

When i purchased my car it was evident that there was a sunroof leak causing water to drop down the windhsield and firewalls,affecting everything electric,I've already had to purchase a new ecu due to corrosion. The black box managed to only be slightly damaged allowing most of its functions to work. Everything else doesn't radio idiot clustee instrument cluster logicon controls,I'm just wondering if it's possible to repair all these parts by cleaning or re soldering their joints

It's a bit of a stretch. It's definitely possible, but you'll be spending a lot of time on that chassis. There's a good chance that a whole bunch of the individual electronics components have fried, the wiring harness might short out in various locations, and yes, there's going to be a lot of corrosion. Some components are definitely going to be beyond salvaging, and no amount of soldering will rescue them. You'll be spending a lot of time chasing little gremlins out of the electronics system, so I'd frankly redo the entire wiring of the car. It's going to be a massive time commitment (regardless of how you look at it, this car will inevitably require a lot of work to get back on the roads), but you'll get really familiar with the electronics of the car.

Although, it'd be easier to judge if pictures of the carnage were available.

If you decide to redo the wiring, it'd be a great opportunity to weed out unnecessary wiring, do a battery relocation, and replace wiring that's over a quarter of a century old. All RX7 wiring harnesses are the same within each series (except turbo vs NA), regardless of whether you had cruise control, auto adjusting suspension, a sunroof, rear hatch wiper, etc. or not. If you decide on a total emissions delete, you can simplify the wiring even further.

Thanks I've had the car for almost a year now and I'm just now getting into it,it runs great and the only electronic damage is like i said the stuff up against the firewall. Maybe I'll have to replace those parts and pull the dash apart to look at all my wiring too

Ah, I didn't realize it was already running. Well, that's a massive leg up from where I assumed you were at. Definitely pry off the dash and have a look, that'll probably help you find anything egregiously wrong with the wiring back there. The interior isn't designed to be weatherproof, so it doesn't have the same safeguards as the wiring in the engine bay. Good luck

Ok got the dash apart and the only thing I broke was the defrost vent haha. The body of the car itself isn't rusted but there's still corrision,all the plugs seemed to be corroded and the grounds look terrible. Any idea on what to use for the plugs and connections to clean them? And as for the gauge cluster and other things there boards are all a little corroded too.

Got A couple pics too