From an old Bilstein article, I did copy/paste:
For a 2013 Ford Mustang, Bilstein B8 shock absorbers will have less overall travel than the original equipment manufacturer (OEM) shocks, not more. This is because the B8 series is specifically designed for lowered vehicles.
Key differences between Bilstein B8 and OEM shocks
· Purpose: The B8 shock is engineered for use with aftermarket lowering springs, not with the factory-height springs. Its primary function is to maintain proper suspension travel and control within a shorter overall range, which helps improve performance and handling on a lowered car.
· Travel and length: Bilstein achieves this by shortening the shock body and rod length compared to a stock-height shock like their own B6 or the factory equivalent. This keeps the suspension from "bottoming out," or hitting its full compression limit, when paired with shorter lowering springs.
· Performance: B8 shocks are often more firmly valved than OEM units to provide a stiffer, more performance-oriented feel. This helps manage the higher spring rates of lowering springs and improve handling, cornering, and stability at speed.
· Ride quality: While the B8s are stiffer and performance-focused, Bilstein's technology helps them maintain a high level of comfort compared to other aggressive performance shocks. However, the ride will be noticeably firmer than stock, which some drivers on rough roads may find unpleasant.
Do not install B8s with stock springs
Using Bilstein B8 shocks with your Mustang's factory-height springs is not recommended. Doing so would place the shock piston in an incorrect position within its travel range, leading to a poor ride and the risk of damaging the shock. For a performance upgrade on a Mustang that remains at stock ride height, the Bilstein B6 series is the appropriate choice.
