I'd buy the Raider tomorrow if it were Storm Grey. Stealth Grey does rather look like someone's polished it with a sheet of sandpaper!
It's matt paint as I'm sure you know. I'd just buy it if I was you. Very few cars around with that heavy a spec. Grey is your preference too, no? It's grey.
You could be waiting for a year or more for what you seek colour-wise. Then you have to factor in the options. Let's say you only want Recaro's and the Cup chassis as options and will forgo Speedline's to buy them afterwards and are happy to deal with sat-nav, or the RS monitor, or neither, and take either the Cup, GT or no spoiler, it begins to lower your chances considerably.
Of the 213 Albi Blue, 71 had Recaro's, 160 with Cup chassis
Of the 147 Racing Blue, 57 had Recaro's, 118 with Cup chassis
Of the 55 Alien Green, 20 had Recaro's, 46 with Cup chassis
Of the 144 Nimbus, 37 had Recaro's, 98 with Cup chassis
Of the 43 Storm Grey, 23 had Recaro's, 31 with Cup chassis
Your pool of cars has just dropped from 602 to 208 based on the Recaro's. Not including those written off, SORN or unlikely to ever be for sale, or with mileage over 20K; which for a car produced from 2010 to 2012, even a car from 2012 with average mileage should be ~30-40k.
Bring in the Cup spoiler and it's:
14 Albi Blue
22 Racing Blue
3 Alien Green
23 Nimbus
6 Storm Grey
You can easily retro fit the Cup, but from factory, you're down to 68. I won't do the Sat-nav/RS monitor by colour, but your looking at 63/55 respectively across all colours. For a black roof, just 33 across all the colours you prioritised.
Good luck, but factor in a long wait, or a lot of luck. Go and see the Raider. You might like it : )