New to the M-body

hey guys I just recently picked up this 2dr 78 LeBaron believe it’s a medallion for a steal. Being new to the m-body I have some questions that may come of newbish lol.
First question: are all m body platform parts interchangeable? Suspension and brakes and such? Like Ik late 60s darts and early 70s darts share very similar parts and can interchange without much headache. Is this the same with the m body?

Second question: is there any aftermarket support for these cars? I’m in need of...

New to the M-body
Author: TheSkunk