Nice car.

Dont cop it out, and ditch the strobes, if a cop sees you using them even on private property they can make life very miserable for you. One guy was using his spot light cops saw him, he got stopped four times in two weeks, each time the cops tore his car apart looking for illegal lighting. several others have been stopped and harrassed several times for just driving one. also get used to people riding in your blindspot and driving 5 under in front of you

skip the K&N, a member did a dyno test and actually lost 2HP from it, the big restriction is the heads, and intake.
a Performance Improved intake is good for about 15HP
You can get a Marauder airbox and 80MM maf, and a 04 PI zip tube and pick up 20-25 HP.
You wont really pick up any power over the stock duals unless you modify the motor with forced induction or ported heads.
with gears dont go 4,10s with out a tune, otherwise at full throttle you will hit the rev limiter before the trans shifts

Suspension/Drivetrain FAQ read this before you post. Bushings, springs, etc all here - GrandMarq.NET - Panther Headquarters Suspension FAQ, written mostly by me and a guy who beats WRX in auto crosses in a 91 Crown vic wagon
front shocks are 67-81 Camaro, rear shocks are fox body mustang. springs are Chevy parts also. 64-early 70s mustang wheels fit, any other pre-05 mustang wheels will require 1.25" spacers

Angry Duck Tofu Racing is a good place to get parts