I have a stock 03 350z track and am about to purchase a zex kit, I was wondering what problems, if any, will i run into with a 75 shot? I have the colder plugs.

 

Don't take this the wrong way:

If you can find this sub-forum, then you can find your answer here to your rudimentary question.

Start by reading the stickied threads and by searching for your answer. I assure you that more information will be had by following my advice.