2003 BMW M3 - The Cage

The extra diagonal brace in the rear, taking the cage from six to eight points, costs an extra $350; the pyramid door bars are available for $700 per door. Glifberg's cage has just one of those, on the driver side, taking his total cost to $4,950.

Now is a good time to point out why the cost is what it is. This cage has been fully fabricated from the ground up and grafted into the E46 unibody; it isn't some cheesy one-size-fits-all bolt-in number. Additionally, the mounting points where the cage actually attaches to the unibody are plinths which have been fully welded into the chassis. According to Otoupalik, there are two schools of thought when it comes to attaching a cage to the body. The old-school method simply attaches the circular cage tubing directly to the unibody metal, sans plinths. Evosport's method basically adds those plinth structures in between the cage tubing and the unibody, offering roughly four times more surface area than traditional methods where the cage connects to the chassis. This helps dissipate impact energy over a greater area, through entire cage and unibody and away from the driver-which is the whole point of installing a cage in the first place.

Safety aside, there are also performance benefits gained from installing a solid, well-fabricated rollcage. Obviously it strengthens the unibody overall, but also stiffens and strengthens the suspension pick-up points. This allows you to run a more compliant suspension at the track, which in turn improves grip, handling, and power deployment. It's a common misconception that says the stiffer the suspension, the better.

"A compliant suspension is the goal of any track car, not to be stiff and low," Otoupalik says. "A more compliant suspension gives you more grip on turn-in, exit, and mid-corner-a nice stable platform. You swim through the turns, not skid through them. When a car is handling beautifully, it feels slow. It's not stepping out or losing traction, it just handles right. It may feel slower that way, but the clock says it's faster."

A few words about welding- another important consideration in any custom-fabricated rollcage is weld quality. Pretty welds-smooth, straight, looking like a flattened-out roll of coins-are not just aesthetically pleasing. They're indicative of a seasoned fabricator, one who knows his machinery and who has mastered all aspects of the weld: patience, temperature ranges, speed control. On the other hand, ugly, chunky welds may not only indicate an inexperienced or inattentive welder; they could also be indicative of improperly fitting bars and a poorly conceived structure. Good welds will usually speak volumes about the overall quality of fabrication.

With the cage assembled and grafted into the unibody, the final stage in the chassis-prep process is getting it painted. This, too, is a very important step. Without paint to protect the chromoly tubing, it will quickly begin to rust-and given your investment to this point, you definitely don't want that. Evosport usually uses light colors, like white, on its race cages to help with heat dissipation; it can get damn hot inside a hard-charging racecar. Glifberg chose Porsche GT3 RS orange, still a suitably light color but one that shows his own personal flair. Orange is a notoriously difficult color to apply and it took three attempts to get it all even, but the results speak for themselves.

With the cage done, it's time to start looking into mechanical performance upgrades. In the next installment we'll take a look at a few bolt-on bits for the suspension and engine bay.