No problem for have any measures of the "wire" object in Topmod because you enter a value by hand who can be something like 1 to 0.0001! (depending of the original)

The only problem now in Topmod is that : you can modify something existing but not add an another object
So paste our objects in any 3D prog and re-import it in topmod for have your "grid wire" :)
Ps Cool car!
So next time post your "piece" to wired and not the entiere car :)
Else it's the entiere car ( but heavy file I presume) you can kill easily quasi all parts in just one selection of facets :)