can they be replaced under warranty?

not a wear and tear part like rotors. even if they did crack they would say it was abused....

Our rotors are Centric blanks that have been machined. Centric is the parent company (OE replacement arm) that owns Stoptech Brakes.

Stoptech is Centric's performance division and does sell various levels of their brake rotors with many features like heat treating and so on which raises the price substantially.

I personally run our rotors on my Z, my Wife's personal Z had a one-off set of Slotted rotors made specifically for my 2006 Dodge Ram 2500 Tow Rig. Quality wise, I highly doubt you will find a single difference between our rotors and a equally matched pair of Stoptechs. Maybe our boxes are not as nice....

Correct...take a look at the "Little Grey" Nissan warranty book. Unless the rotors have a clear issue immediately after you purchased the rotors (like explode as you are driving off the lot), they will not be covered whatsoever. Brake pads, tires, wiper blades, fluids and so on are considered to be a consumable part and is not covered.

I have the stop tech set up minus the pads. (Which I forgot I had put away in my tool room.) The stop techs wore through my pads real quick. 8875 miles on car. 5000 on stop tech lines & rotors. Kept my new S tune pads on.
Almost forgot I had replacement pads & ordered S tunes again for my car. (Too much on my mind). Anyway, at least, I once again have a backup set. I don't know if these stop tech pads will last longer than my S tunes? But I ate through em. I will post up when I eat thru stop techs. And go back to Stune. Hopefully they will last longer.
Stop Tech does truely help improve stopping and performance feel. I'm truely happy with this setup. I bought these based on visual quality and reputation. I'm sure Z1 has a great low cost solution. But Stop Tech is in the business of brakes. Low cost solutions are cool. But I do know stop tech is a brake building company for sure. They're not just outsourcing parts and putting a package together. So I will stick by this product.

DISCLAIMER-
1. I'M NOT SAYING ONE BRAND WILL BE BETTER THAN THE OTHER. JUST GIVING YOU EXPERIENCE.
2. IIM NOT CRYING, MOANING OR COMPLAINING ABOUT MY PADS WEARING EARLY. ITS PART OF WHAT HAPPENS WHEN YOU MOD SHYT. JUST GIVING A FACT AND OPINION.

If you aren't tracking get autozone rotors lol (and I'm serious)

whats the wear like with your brake kit as far as the carotech pads and drilled and slotted? anyone with experience with these? I have almost 40k on my dd (50miles to work with 40miles of fwy driving) and looking to do a brake upgrade. I have the base sport z.