That last category are powerful additions to a deck but can only include one ACE SPEC card of any type, so choose wisely
Whir of Invention : Instant, casting cost of X generic mana and three blue mana
Being able to play Discard spells is the best way to stick a midrange plan in modern, and Inquisition of Kozilek for sure suit that plan really well
The card sold via online auction site Weiss Auctions for US$195,000, translating into AU$285,000
Excruciator being a compact way to add another angle of attack fits perfectly into a midrange strategy, which relies on being able to adapt its plans against various opponents, as opposed to a controlling strategy, which is much more concerned with the ability to answer incoming threats than finding win conditions