Been using supersparks for a while now (4-6months or so in a few cars) and helped with the testing, so far ive had no failures and can honestley say i am happy to use them in my own cars.
did back to back with the split fires, FET, superspark in the 26 and honestley say they all pulled within a kw or so of each other (all mid 350rwkw's) so they can happily pull mild numbers.
But if you think you are going to gain power from coils you are sadly mistaken, if the std coils are not doing their job then YES you will see an increase but i guarantee if you whack in a nice NEW set of NISSAN coils you will match power with your splitfires and so forth... problem is std nissan coils are as dear as poison and it is simply easier and cheaper to use aftermarket.