Black cars are gorgeous when clean, but it takes A LOT of work to keep them clean safely. Since my black car I've been put of dark colours for that reason, so the OP is effectively asking if space grey has those problems.
With any car, especially black, heres my top tips to avoiding swirls:
1. NEVER let the dealer wash it.
2. NEVER use automatic car-washes.
3. If possible, use snow-foam to loosen/remove as much crud as possible before actually touching the paintwork.
4. Did I say NEVER let the dealer wash it?
5. Use two bucket method with good quality wash mit (not SPONGE) returning to dirty bucket to rinse.
Others will have their own versions I'm sure, but these will help to minimise swirls (I say minimise, cos I think its unavoidable to some degree). Basically, you want to avoid physical contact with the paintwork as much as possible - some people get the snowfoam right and dont need to touch the paint!
No matter what colour car, this is a good idea.