Clamp STEP File Dimension Edits

I have a complete clamp assembly saved as a .STEP file and I need the length of four individual parts modified. All other dimensions must remain untouched so the assembly still fits together perfectly once re-imported into the new CAD files... (Budget: $10 - $30 USD, Jobs: 3D CAD, 3D Design, 3D Drafting, 3D Modelling, 3D Print Design, Assembly, AutoCAD, CAD / SolidWorks, CAD/CAM, Solidworks)