So I've got my hands on Beyond the Rim, but my players are up 200 XP. The game suggests upping the combat NPCs, but my players aren't really combat based. I was thinking...basically adding a setback die to everything? The game suggests giving ranks to NPCs, but I'm not sure if that'd be enough. I'm also thinking of resetting all of the PCs XP down to zero, and I discussed that with the group, but they're lukewarm on the idea.

Does anyone have any experience running BtR for experienced PCs? Shed some light here?

Just adjust all different skill checks as needed. Don't go crazy with it since upping skills too high against your players will turn them off to the idea of even upgrading them in the first place, but make it a bit more of a challenge for them again.

If they are good in negotiating and dealing with people, making the NPCs a little more quirky or irascible. Make those checks more difficult. If they aren't speced for combat, give them a reason to. Show them some slightly more powerful enemies and get them going in that direction.

Dropping them to 0 would be little better than telling them to re-roll characters. Not always the most exciting of options....

Whatever you do, do not drop the PCs back to zero for the sake of one adventure. Best to modify the adventure rather than modifying the PCs. Beyond the Rim is, after all, just another job to the group. It's not so important that the PCs need to scale back to make it more interesting.

I ran BtR with a group that's around 200 xp. As a rule, I upgraded every dice pool by one to give them more of a challenge. I also added Yiyar Clan members as I saw fit, doubled the number of stormtroopers that attacked the Retreat, upgraded the four TIE fighters at Raxus Prime to six TIE interceptors, and generally just threw whatever I wanted at them whenever it seemed appropriate. The trick is to not show the entirety of the threat to the PCs. Always give yourself the excuse to throw more enemies, security systems, or bureaucratic hoops out of no where if they seem to be getting through things too easy. When they first got to Cholgana, my group was attacked by the Nightflyer. My group completely wasted them, blowing it out of the sky in like two rounds. So the Yiyar Clan seemed to be dealt with, which is upsetting to the BtR campaign book. I took that in two directions: they arrived at the wreckage too late and an unknown number of Yiyar clan bastards escaped before they got there. This allowed me to throw however many Yiyar Clan guys at them whenever I wanted. Second, when the Imperials showed up, I purposefully made their coming sound really far away and be impossible to spot. This way they had no idea how many Imperial forces were landing on their jungle planet. Surely more than the handful at their door!

PCs will generally be more terrified and cautious about risks that they can't see or fully grasp. If you show them the full extent of the challenge, then they know they can overcome it. But mysteries always contain danger.