Theres just way to much that determines ride hight. Everything from a tires sidewall profile, to condtition on the struts, and the rim size. For the most part the same spring setup on the same make of car should be damn close. Gotta keep in mind tho that some people either A)don't know exactly which kind of what brand of spring they have, so they guess and B)alot of people actually cut their lowering springs. So don't always compare your car to someone else's just because they "say" they have a certain kind of spring.

Also are you sure your buddy has just the 1.3 in drop teins? maybe he's like choice A and is wrong about what kind he has.