I would go with more neutral colours. No offence to the people on here with all sorts of colourful interiors, but I find it looks slightly tacky / cheap. Black/tan/silver/grey/white usually looks best (even a touch of red)
You can try and be different and go with orange or green, but in the end, the neutral colours are classy and timeless.
Check out what cadillac/audi/bmw does:



I tried the black and silver on my fiero, thought it worked out well:


Thats my suggestion for what its worth!
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