4. Mid perch - It's really easy to bottom out the front end on bottom (stock) perch when offroading at speed. Not a big deal but you will have a dented in skit plate pretty quickly on bottom perch.
5. Bump stop kit - You may already know, but the Raptor has a crumple zone right where the factory bumpstop is located. If you're to hit to hard you can bend the frame in that spot. I'd at least get the SDHQ frame reinforcement kit which is only a $100. But the kits by Outlaw, Icon, or RPG are your best bet.
From there, there's tons of other stuff you can add depending on how crazy you want to get.
I've included a couple must mods