How powering PIC in auto ?

[Gusse]

If you are using surface mounted components (0603 or smaller), then it would be more wise to put ESD protection before any serial resistor. Resistor will burn or change value if you force ESD current to go thru it.
Old thru mounted comps can tolarate more ESD, but even with those I would recommend to do the same.

For ESD protection you can use: TVS, varistor or zeners. All those will give appropriate protection, if you have done your PWB layout correct way. Try to minimize all paracitic impedances (inductances & resistance) from ESD current paths.

BR,
-Gusse-