4mm then... or try and convince BMI to make one for the 415
Relating to my earlier post, some pics to explain it better.
First two, shows the screws on both cars that I measured the distance between (rear two, steering posts, front two, suspension block).
Second two, show the ackerman spacers (red arrow), and wheelbase spacers (yellow arrow).
What I've done is assume all other measurements are equal, so effectively by adding thoose three variables together, I can figure out exactly the difference in ackerman between the two. A large total number means that the longitudinal difference between inner and outer l joint is larger... effectively putting the steering link at a greater angle.
Because the spacings are different on the two cars, the ackerman setting is different, which affects the way the car turns. I'm trying to get my MRE to handle as well as the evo on the rug, so hence why I've added spacers.