Good advice thepottleflump and (CZ)enda (though it's Rosso Corsa 140 or 854/F, tsk tsk

!)
Now since they made Unos in Pretoria until a year or so ago, I'm sure there will be more red doors around. I only saw one slightly-rusty Uno in coastal Durban; in general I was impressed by the condition of the Unos rolling around (though many of them were only a few years old, of course). The climate in hay-fever-capital Centurion was ridiculously dry (didn't rain for 35 days!)
That red is nowhere near as bad as 'Punto Pink' (as I call it) and I'm sure it will polish up nicely. Imagine the bumpers and black plastic black again, and you have a smart little driver.
Fitting air conditioning is going to be expensive - more than the value of the car. Painting it black sounds like a good idea until you appreciate the work involved - it would be much easier to polish what you have! I used to paint cars different colours, but have pretty much given up this lark unless the car is stripped for some other reason.
You just need appropriate products. You don't want waxes and polishes from an auto accessory shop until later on (for preservation); to get the colour back you want something like 3M Finesse-It from a paint shop. You can use a polishing machine, but the results obtained in polishing by hand are just as good. And the cheap vibrating polishing machines of the two-handled type are USELESS, save your money

You need something that looks like an angle-grinder and does several thousand RPM. Or, use your hands. You really will be surprised. Please take a look at
https://www.fiatforum.com/uno-styli...aint.html?highlight=polishing+roof#post432996 if you want to spoil the surprise.
You could try tightening the clutch cable a little anyway. Slacken one of the two 10mm nuts (holding the other nut), then turn the nuts a few turns towards the cable (5mm should be enough of a difference to notice.)
I've had good results with red paint matches, but only if the rest of the car is polished-up FIRST before painting.
I think though, given the number of Unos around (thepottleflump: there are LOTS

, and loads of Mk1 Golfs - yes, Mk1! - also made locally, don't know if they're still in production) that you are better off to find a replacement red door and bolt it on yourself.
Hope you have fun with it!
-Alex