Thinking of buying s13, but how harmful is 55-75shot of Nos??

[ucfz31s13]

Car has 83k miles, pristine condition w/ injen intake, greddy exhaust, headers, flywheel, clutch, e-fan, and zex nitrous kit. Synthetic oil being used as well. Has only seen 4-6 bottles of nos, some 55 shot, but a couple 75 shot. How bad does this amount hurt the engine?? Is 4-6 bottles a lot, and is this something i should be worried about, or should the motor still be fine. Car idles, runs great, but wondered if the nos has done any harm to the motor. I know when the 75 shot was used the timing was retarded. Other than that, car is in excellent mechanical shape inside and out. Are there any things I should look for?

Thanks.

z

[I am Technoman]

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