2013 mazda 3 question
 

I would like some help on how to make my stock 2013 mazda 3 quicker, i would like to make it be a sleeper but want it to be quick
any suggestions on how to make it quicker and a sleeper under 800 bucks...

You can add a cold air intake system, do a throttle body ground, throttle body coolant bypass,install some msd headers

Where should we buy all these things? And what company's provide the best parts?