Philippe Hurbain Wrote:BTW, what about file size/number of polys?
That depends on the type option in the placement panel, for static/dynamic references it's just a bunch of type 1 lines (one per e.g. chain link). But when you use the 'deform' type every vertex of the (flattened) donor part will be transformed using a different matrix and thus the resulting part will 'explode' into type 2..5 lines for each reference of the part.
If size is an issue you could always use the normal references type although personally I think those should only be used for things that are loose parts in real life too (chain links). Pneumatic tubes etc should always be deformed imho, but the option remains.