id buy the storm grey now and not look back. Youll have the window down listening to the engine anyway, a/c is for homos.
To answer your question, yes red calipers is the easiest way to check if a car is 'cup' from the outside. But don't forget you can ad the 'cup pack' to a 'full fat' clio and you'll get the red calipers and lower suspension. Ht to really looks out for is a 'cup' sticker on the B pillar and the interior is different on the cup - the interior is the one thing that properly gives it away.
:welcome: to the site.
Or another way;
Silver calipers = Full fat
Red calipers and a key card = Full fat with cup pack
Red calipers and a CHEAP key = Cup.