I’d personally go for a lighter shade than black. Although black alloys on a red car is quite a good combination, IMHO black alloys only really look clean just after they’ve been washed - at other times they can have the appearance of always looking dirty as a result of the build up of brake dust and road dirt.
In terms of colour, my preference would be to go for grey (anthracite, gunmetal), smoked chrome or a dark silver and a powder coated finish. All of those colours seem to hide brake dust and road dirt well, and unlike gloss black, won’t show swirl marks.
I’d avoid anything with a diamond cut finish (also referred to as ‘machined’ or ‘polished’) as the long term durability of lacquer applied directly to a diamond cut surface isn’t particularly good. Diamond cut alloys quite often succumb to white worm corrosion at around three years old (some times sooner), especially if they’re on a car during the winter months and subjected to winter road conditions. White worm corrosion can be removed by getting the alloys refurbished (a top quality refurbishment would cost in the region of £120 - £140 plus VAT per wheel), but it often comes back a couple of years later. Also, because of the process used to refurbish diamond cut alloy wheels (cutting a layer of metal off the face of the wheel), they can usually only safely be refurbished twice - more than twice and too much metal will have been removed, which would compromise the structural integrity and safety of the wheel.