I am aware that any modding will bring my engine out of warranty. I`m just qurious and like modifying engines,that is the only reason I do this.I have never ruined an engine so far ,and this modifying has only made good engines better. My asp certainly liked the treatment and idles and trottles just as well as before. remember all grinding and polishing is done on the outside of the sleeve. No messing up on the chrome or ports itself, just chamfering the lower part of the ports and sleeve.Its no big deal really and the engines wake up a bit