Car Tune or a Throttle Controller ?

Tuning will help you get more from your engine. More power, more torque.

Some handheld tuners have also the possibility to modify the Throttle response tables on your ECU.  The only limits are the ECU will only allow up to 15% throttle response improvement,  anything beyond that value and the ECU will not accept it. 

A Throttle Controller will help you improve the Throttle response by up to 200% increase.

Yes, you may use both a tune and a throttle controller.