I have the optional pearlescent Thunder Grey paint, and I have never done anything to it. Besides wash by hand, only by hand with unival type car soap, then dry wash over the car with a dry rag. 8 years later my Mirage still looks glittery if it's clean.
Like you can see the colour of your shirt in the reflection, and looks almost purple sometimes. Like a nickel effect. So maybe the roof has some fade but very little. I worry about products doing damage so I just leave the paint be. I use krown for rust control and seems to work well. Just smells weird but is worth it
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View my fuel log 2014 Mirage ES 1.2 manual: 42.2 mpg (US) ... 17.9 km/L ... 5.6 L/100 km ... 50.7 mpg (Imp)