Brad Curtis Alpina Roadster S is an ongoing project which started as a standard Alpina. Although slightly improved over the standard Z4 models, the suspension, brakes and differential still left much room for improvement. The first thing to be replaced was the suspension, Intrax 1k2 struts were fitted along with a rear limiter kit and uprated front bushes. H&R anti roll bars and Turner Motorsport rear camber arms completed the upgrade. AP racing brakes were then fitted front and rear but only after the decision was made to fit an M3 rear axle complete with LSD and 3.62 ratio. M3 front hubs were fitted at the same time. Fast road pads were installed as the car is to be used primarily as a daily run around.
To allow clearance for the brakes the Alpina rims had to be replaces with CSL items and 10mm front spacers. An OEM strut brace has been fitted after minor modification to allow it to clear the inlet manifold. Now that the handling and brakes are transformed our attention is turning towards styling and performance. The Alpina already produces over 300bhp and has substantial torque however there’s always room for improvement. Engine wise modifications have been minor with a GruppeM carbon intake and exhaust modifications being the only upgrades so far but a custom built exhaust using Supersprint parts will be fitted. We are considering the possibility of fitting a supercharger in the future which would be modified to fit by ourselves and may incorporate a forged crank and rods with lower compression pistons. The side skirts will be replaced with aftermarket items at some point however the option of an RS style bodykit is also a possibility.