Dude this is sick, I’ve got a full bolt on stock tune fiesta and looking to jump to a good 91 tune with the s280, and I wanna get over the 300hp hump, even though I daily it, I can obviously switch back and forth between tunes for when I’m going to work and when “I’m going to work”, is it possible with the pump gas to reach 300
it's on the bleeding edge of "yes it's possible" but right in the middle of "you really shouldn't do it"
i mean are you asking if 300 WHP or BHP is possible? WHP is pretty relative and you're gonna get different numbers compared to a simulated number with Vdyno vs a Mustang dyno. anyone here who has gotten 300WHP (again, taken with a grain of salt unless done on a Mustang dyno) on pump gas has pushed the hard limits of what the engine can handle and even then i'm not sure if they actually got to 300WHP without grenade'ing their engine. if you do an ethanol blend, a decent amount of people have hit that number on a big turbo with a reliable tune. but on pump gas, a 300WHP tune shouldn't be your goal. especially if it's your daily driver.
300 brake hp though? yeah you can hit that.
edit: also not sure what you mean by "switch between tunes". if you read around the forum, the limiting factor of HP on the 1.6L is hitting the knock limit (if you're like me when i first went down this road you'll have to read up on that). based on most people's posts, you're gonna hit that limit on 91OCT before you get 300WHP. and asking a tuner to go past the knock limit is not something anyone here would recommend.