They extend the overall length of the coilover assembly. Which at full droop will cause the cv's to hyper extend, and will push the ball joints past their limit.jdub3333 said:i have the revtek 3" w/top out spacer. what exaclty is the function of the top out spacer? i asked about running ome 881's with the spacer and it was suggested that i might have to remove the top out spacer. what would that change? anyway i was wondering?