The list is getting bigger, and the budget stays the same

Im still looking at parts for upgrade on the Stang, and the more Im researching, the better the performance is getting. Top speed will remain the same, I don't want tickets. So far, its shaping up like this:

Car alarm: $250
Spare Keys (2, programmed) - $21
K&N Fuel Injection Air Box replacement Kit - $214
Bosch +4 Spark Plugs & Low Attenuation wires - $30
Speaker upgrades - $180
Carwash accessories - $28

Hmm, that burns off $723 of income tax money I don't even have yet...