i am planning on keeping the map system link compadible with my no-mods xbox, and so i am trying to keep the same polys... no more/no less so the filesise with the orignal are the same. but when i export from Milkshape it dosent save changes!? well, i make the changes (as shown in image below) then i go to File / Export / Wavefront OBJ, then i overwrite the orignal, and check the sise, and the sise is the same wich is good, but when i open it, NOTHING HAS CHANGED!? i dont know why, its just not exporting the changes! and i also dont know how to re-improt the model over the orignal. if somone can help out then that would be great.

The "complete tutorial to modeling" tut dosent explain how to overwrite the games orignal models, just add a whole new thing .. that would make it incompadible with my legit / no mods xbox over system link, wich is bad, and also adding more polygons would change the filesise wich is also bad as i just want to inject the model over the old one.