Glueing parts that have been painted

Once you've painted the interior and suspension parts, how do you glue the parts together while them still being strong? Because all the stress of the join will go on the paint itself instead of the plastic. Right?

Also do you need to sand and prime the interior parts (seats) before brush painting them?

Cheers guys

for glueing i always scrape the paint off the places to be glued as the glue only bonds the plastic really well.

Ok. But if the parts are small you will be able to see the scraping of the paint that you took off, right?
What about if you need to prime and sand the interior?

I use an X-acto knife to scrape as little as possible off the part.