i'm about to put in an MSD SCI box but i found out that my coilpack is erratic
it still does its job but on a dyno the spark goes up & down (very unsmooth)

i found some S4 coilpacks (88 AE) for a decent price but I've heard ppl say that S4 packs can't take on an MSD very well....is this true or false?

should i get a good S4 coilpack with the risk of it maybe dying/malfunctioning (if that is true) or stick with my erratic S5 pack?

 

the coil packs don't look any different to me, but I'm not sure.

 

S4, S5, Turbo, N/A they are all the same.

 

S4 & S5 same

 

I have been running an MSD on S4 coils for years with no problems.

 

thanks guys!!