BMW introduced the X3 M to blend thrilling performance and aggressive styling with the comfort and practicality expected of a true daily driver. It delivers everything enthusiasts love about an M car, enhanced by the X3 platform’s versatility. Still, for some, factory performance isn’t quite enough. They’re looking to push it even further, lowering this already sport-focused SUV to sharpen its stance and extract every ounce of capability from the X3 M, all without compromising everyday functionality.

Enter AST Suspension and its Adjustable Lowering Spring (ALS) kit, engineered to dial up performance without compromising ride quality. In collaboration with our friends at Thompson BMW and Thompson Performance Group, we are outfitting an X3 M with AST’s application-specific ALS kit (ASTALS-21-015) to see firsthand if the Dutch engineers got it right.

Spoiler alert: they absolutely did.

Roots in Motorsport

AST Suspension has been engineering high-performance suspension components for more than 25 years, with adjustability at the core of its success. Renowned for its coilover systems featuring both height and damping adjustment for street and motorsport applications, AST manufactures everything in-house—from springs to shock bodies. Each kit is produced in the Netherlands at the same facility where it’s engineered, assembled, and shipped, ensuring complete quality control from start to finish.

As vehicle technology has advanced, so have the expectations of enthusiasts. Today’s drivers want a suspension solution that enhances performance and offers adjustability, without compromising OEM electronically controlled dampers. AST’s application-specific height-adjustable spring kits are a natural evolution of its product lineup. Built on more than two decades of coilover expertise, the company introduced its first Adjustable Lowering Spring Kit for the BMW F8X M3. Since then, the lineup has expanded to more than two dozen vehicle-specific applications, with thousands of kits sold, proving the concept delivers exactly what modern enthusiasts demand.

A Lowered SUV?

“Why would I want to lower my daily driver SUV?” If you’re reading this, then you’ve likely already asked yourself this question, and even if you can’t fully explain it, you know the idea makes sense. Let’s start with the facts.: Lowering your SUV drops the center of gravity, which reduces body roll in corners and nose dive under braking. The result? Sharper handling and a more planted feel behind the wheel. There are practical perks, too; stepping in and out is easier, and loading the rear cargo area takes less effort. But let’s be honest. For most daily-driven SUVs, the real reason isn’t lap times, it’s presence.

Reducing the wheel-to-fender gap transforms the entire look of the vehicle, giving it a more cohesive, intentional stance. Height-adjustment is key to nailing the perfect appearance, and when the main reason for lowering isn’t on-track performance, sacrificing comfort and functionality can turn many people away. AST’s lowering springs are engineered to be approximately 15% stiffer than factory—noticeably tighter, but far less aggressive than many competing options. The result is improved responsiveness without compromising ride quality or everyday drivability. Even better, the factory dampers are left untouched, so there are no warning lights on the dash, and that “comfort” button in the cockpit still does exactly what it’s supposed to do.

So Easy, a Certified BMW Technician Can Do It

The installation process is relatively straightforward: remove the OEM strut-and-spring assemblies; replace the factory springs and bump stops with the provided bump stops, springs, and adjustable collar; and reinstall. Of course, on modern vehicles, “straightforward” can still mean time-consuming, so we partnered with the experts at Thompson Performance Group. They’re no strangers to lowering BMW SUVs, having previously built the BMW X5 M Competition for the Turn 14 Distribution x BMW CCA Dream Car Raffle. Their willingness to install the AST ALS kit speaks volumes. Shops of that caliber don’t put products on customer cars unless they stand behind them.

Once installed, fine-tuning the ride height is simple and requires no disassembly. With a floor jack used to decompress the spring, adjustments can be made using the included AST tool—no need to remove the wheel. The kit provides 0-40mm of adjustment up front and 0-35mm in the rear, offering plenty of range to dial in the perfect stance. In the case of this X3 M—owned by our European Performance Account Manager, Bobby Ashton—the settings are maxed out front and rear. He prefers it sitting low, and the AST kit delivers exactly that.

Living the Low Life

It’s worth noting that Bobby’s X3 M previously ran a competitor’s fixed lowering kit. The deciding factor in switching to the ALS kit was simple: adjustability. Being able to precisely match the wheel gap front to rear is a major advantage of AST’s ALS system. Whether you prefer a level stance, a touch of rake, or something more aggressive, the ALS kit puts that decision entirely in the owner’s hands.

After a few weeks of daily driving, Bobby’s feedback was clear. The most surprising improvement was ride comfort, especially at the lowest settings, proving that a lowered SUV doesn’t have to feel harsh. He also noted sharper steering feedback and improved responsiveness, benefits that translate directly to more confident performance driving.

Another advantage of an adjustable lowering spring system is the ability to fine-tune ride height to prevent rubbing when running wider, larger-diameter aftermarket wheels. In this case, that wasn’t an issue thanks to careful wheel spec selection with help from Jereme at Vossen, but the flexibility is there if needed.

BMW designed the X3 M to lean heavily into the “sport” side of the SUV equation, yet there’s still room for refinement. Whether the goal is improved responsiveness, a dialed-in stance, or simply closing up the wheel gap, AST’s ALS kit delivers the adjustability enthusiasts want—without sacrificing comfort or functionality.   

A big thank you to AST Suspension, Thompson BMW, Thompson Performance Group, and Vossen Wheels for providing the products and support that made this collaboration possible.