Maybe the possiblity of making HighSpeed Uni a regular fixture once every month or two. Making them with the Sandbox game version as you have done with Aurea the small 200 solar system. You could make it where the player pays a small amount like $3 or $4 USD to participate in the HighSpeed Uni. Which also keeping all assistant's free for the high Speed Uni.

If it's the young player market you would like to attract to SI. Then Servers like Aurea HighSpeed design is what would attract them. The young do like fast paced action in their games.