In the TSR Workshop. I'm trying to use sims3cri_fts_cri_speedobody as a base for a leotard mod I want to make but I keep leaving something behind. The only things I've changed were the Multiplier and the Clothing Spectacular. What else am I missing?

I don't understand what do you mean with "keep leaving something behind." Can we see a picture?
Do you mean a texture? Check to see if overlay is empty and even the stencils at the bottom of the panel.