Any EXP should be able to get into the spa free regardless of class of service, otherwise it's 45€ (unless policy has changed).
I was once op-upped to business and very much appreciated the 180 lie-flat seats, though the cabin and the food felt a little spartan. The northern lands have a different concept of luxury. Actually, the food was downright weird, especially in coach. But HEL is a very civilized airport IME.