I have a 6al also and i think it helps.
The stock ignition works just fine but if you want more efficiency and a bit better spark by all means get one but if you're looking for mods, an ignition system is more like a luxury.enjoy your new stang!!
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90 LX 5.0 ,bored 302, MSD 6AL, Twisted Wedge TrickFlo HDs, World class T5, BBK fender cold air induct., 70mm TB,Edelbrock performer Intake, aluminum Drve shaft, 3.55 Gears, Long Tube Headers to Flowmasters.