MSD Coils put out about the same as the 97+ */C Coils. I would think the aftermarket coils make a little more power.. but you won't notice it. The MSD coils are a little cheaper versus purchasing the 97+ */C coils [new that is]. Personally, i'd buy the MSD Coils.. or the like. I have some Accel coils, but I heard they are prone to failure [mine have been fine so far].
You can purchase the new 97+ */C Coils from gmpd, or search junkyards. The MSD'* can come from Summit or Jeg'*. Summit has free shipping.. and I believe the price is the same..
'89 SSE - GX3 -190k, 155k on body - Back for another ride.