Is there an official parts list for an DR4B? Also, since the top linkage is longer than the bottom, causing the path to travel at an arc, how will it effect my robot if i make the top and bottom equivalent so it travels in a direct linear path?
A traditional DR4B has the top and bottom equivalent so that it lifts straight; one of the many advantages of a DR4B. For us to know how it will affect your robot, we will need to know more, but you usually should have it lift linearly.
Yes, there is an official parts list. You should only use the part in the list. You can not use any not in the list.
the travel path of the upper arms depends on the length of your upper arms and lower arms
Where can i find the parts list?
read the game manual. Any parts listed there are legal.