@tubetime
If you will want to attach anything to original plastic I found that apart from bolting together the best way would be to weld plastic with a fine steel mesh like here in the video. https://youtu.be/KJTrNINAs0o

You can just use a regular soldering iron for this and for the small parts you'll need a finer mesh, can find it on amazon https://www.amazon.com/dp/B0B3T3ZBSR . Holds much better than the glue