Hi guys, I own a 2012 Felt Nine Sport and am looking to upgrade my shifters. They don't shift as quickly as I would like.

The bike comes stock with:
9 speed Acera shifters


Shifters:
Shimano SL-M390 9 speed Rapid Fire
Front Derailleur:
Shimano FD-M430: top swing
Rear Derailleur:
Shimano Deore FD-M592 Shadow, long cage 9 Speed



What would be a compatible shifter I could upgrade to?

Thank you,
Carlos