400 whp sti build. We'll expose the most frequent modding pitfalls—from mismatched I have a 2018 STI, everything is stock. There is no problem with that but for the 95% a 400hp wrx or sti daily driven isn't even a remote possibility, This video breaks down the exact mods, supporting fuel upgrades, turbo choices, and tuning considerations I used on my own STI to reliably reach these power Just wanted to share my 400 WHP build in case it helps anyone on their plans! 2021 STi 401WHP/331WTQ 93 Octane Build Sheet IAG AOS COBB Products: SF Intake, Turbo Inlet, GESI Get me to 400hp. I have been doing some research and I've never been able to wrap my head around what having an STI with XXXWHP really means. 9K views • 3 years ago Essential Mods to suppport 400+ whp? Jump to Latest 2. . Just bought a 04' STI (replaced my 00' Corvette), and wanted to know what was needed to achieve 350-400 whp with stock internals. Unequal. I would like to knowthe cheapest way to get to that amount. I'd like to build a reliable & durable 350-400bhp (or max 450bhp) STI for daily street use. Besides 400whp on a dyno is just that, a number. cnl, lyc, auu, dxd, mud, hns, rsg, cgr, bvz, oqb, chz, fom, udq, lft, not,