Machine guns.
Something like a quad (mag mount) Browning .50 cal setup.
Slow me down on my daily commute will you? *ratatatatatatattat*
this
altho 50s are a bit overkill, id go with quad 7.62 gimpys, just the right amount of stopping power and much lighter

then twin grenade launchers and the usual oil slick dispenser and tyre spikes. a rocket launcher would also be a handy addition.
then a fark off pwerful engine n brakes n suspension

ooh and a couple of fit birds scantily clad to service the car and me.
god is this too much to ask?