Hey Mark, welcome to the world of TorqueCars and congratulations on your BMW 3 Series E93 325D M Sport! It's a fantastic choice, especially with that hardtop convertible for enjoying both the performance and the sun in Bedfordshire (you do get some sun I'm told up North!).
With a budget of up to £1k and your goal to upgrade handling and suspension without lowering the car further, you're on the right track thinking about the balance between springs and dampers.
Given that your car is equipped with M Sport springs, which are already designed for a sportier and lower stance than standard models, sticking with them can be a good choice if you're satisfied with the current ride height.
Dampers/Shocks Upgrade
Considering your budget and objectives, upgrading the dampers/shocks while keeping the M Sport springs seems like the best approach.
High-performance dampers can significantly improve handling by better controlling the spring movement, reducing body roll, and enhancing the overall feel and stability of the car without affecting the ride height.
Look for high-quality shock absorbers designed to work with the M Sport suspension.
Brands like Bilstein, Koni, and Sachs offer products that could meet your needs. Specifically, Bilstein B8 dampers are engineered for cars with a lower suspension, making them an excellent match for M Sport springs.
Additional Handling Upgrades
Aside from dampers, consider these upgrades to further enhance handling within your budget:
- Anti-roll Bars (Sway Bars): Upgrading to stiffer anti-roll bars can reduce body roll during cornering, which sharpens handling and improves the car's responsiveness.
- Strut Braces: Installing a strut brace can increase the rigidity of your car's chassis, leading to better handling and steering precision, particularly during high-speed cornering.
- Bushings: Replacing worn or soft rubber bushings with polyurethane ones can also improve handling by reducing flex in the suspension components.
