KellTrac S550 Mustang IRS Bushing Upgrade Kit, Level 2 (KTI-BUK15L2) - 2015–2023 Mustang
The KellTrac Level 2 IRS Bushing Upgrade Kit is designed for S550 Mustang owners who want total rear suspension control without sacrificing street manners. This comprehensive system addresses every major deflection point in the factory IRS—subframe, differential, knuckles, toe links, and lower control arms—delivering a dramatically more stable, predictable, and confidence-inspiring driving experience.
Factory rubber bushings flex under load, causing wheel hop, inconsistent alignment, erratic toe change, and unnecessary driveline stress. The Level 2 kit eliminates those weaknesses using a carefully engineered blend of billet components, spherical bearings, monoballs, and proprietary rubber bushings—each selected to maximize performance while keeping NVH increases to a minimum.
Whether you’re a spirited street driver, drag racer, road course enthusiast, or autocross competitor, the KellTrac Level 2 IRS Bushing Upgrade Kit transforms how your Mustang plants power, responds to inputs, and stays composed under extreme load.
Features – KellTrac Posi-Loc System
- CNC-machined lightweight billet design
- 6061-T6 billet aluminum with black anodized finish
- Precision fitment for maximum subframe control
- Zero increase in noise, vibration, or harshness
- Industry-first rear lower design replaces factory bushing stop plate
Features – Rear Lower Control Arm Bearing Kit
- Most proven S550 lower control arm bearings available
- Super-strong CNC-machined steel bearing bodies
- Industry-leading durable coating
- 6061-T6 billet aluminum offset spacers
- Proprietary BMR 1-inch spherical bearings
- Minimal NVH increase, highly recommended for performance builds
Features – Polyurethane Centering Sleeves
- Extremely lightweight design
- Precision-sized for accurate subframe centering
- Zero increase in NVH
- Industry-first polyurethane centering sleeve design
- Installs into front subframe bushing centers
Features – Monoball Toe Bushing Kit
- OEM-designed, engineered, and manufactured
- Spherical monoball design for drastically reduced deflection
- Outlasts factory rubber toe bushings
- Zero increase in NVH
- Reduces erratic toe change and helps lessen wheel hop
Features – Differential Bushing Upgrade Kit
- OEM-designed proprietary rubber and billet construction
- Higher-durometer rubber for improved performance
- Significantly longer lifespan than factory bushings
- Minimal NVH increase
- Lowest NVH of any full differential bushing replacement kit
- Reduces erratic differential movement and driveline stress
- Lifetime warranty
Benefits
- Reduces wheel hop and unwanted rear suspension movement
- Centers the IRS subframe to the chassis
- Improves handling, traction, and overall vehicle feel
- Helps prevent premature bushing and driveline damage
- Can assist in reducing driveline vibrations
- Reduces pinion angle change under heavy wide-open-throttle loads
- Minimizes unwanted suspension geometry and alignment changes
Fitment
- 2015 Ford Mustang
- 2016 Ford Mustang
- 2017 Ford Mustang
- 2018 Ford Mustang
- 2019 Ford Mustang
- 2020 Ford Mustang
- 2021 Ford Mustang
- 2022 Ford Mustang
- 2023 Ford Mustang
Kelltrac Terms Of Service
Kelly considers his Kelltrac line to be a specialty line for a unique customer base and has his own terms of service in addition to Beefcake Racing's. You must accept these terms on all Kelltrac orders. Please read shipping times, cancellation, and returns. If time is of the essence, we do have other options that can ship right away / quicker. Just reach out to one of our sales associates at Beefcake Racing.
Cancellations & Returns
KellTrac Innovations does not accept product returns. Once your order ships, you own it and we will not accept it back - NO EXCEPTIONS. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Due to the custom nature of our business and product offerings, we charge a 20% order cancellation fee, period, non-negotiable, no matter who you are. Orders can only be cancelled before the product ships. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Leadtime
Please be aware that most orders ship within 2-4 weeks. In some (rare) cases, orders can take up to 6-8 weeks to ship. Holidays can severely impact these lead times. *DO NOT CONTACT US ABOUT YOUR ORDER UNLESS IT IS OLDER THAN 20 BUSINESS DAYS!* If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
CA Residents: WARNING: Cancer and Reproductive Harm www.P65Warnings.ca.gov
