After months of looking on forums and YouTube I bought a used 2017 Fiesta ST yesterday. Really nice shape 25k miles and no mods. I’ll be doing a stage 1 in the next few weeks. I want to make sure I don’t kill the warranty if I need it. I actually enjoy driving again. Hopefully after 60k I can see if getting to 300 whp is attainable. I plan on a bigger turbo. Is this attainable on 91 octane?