Recommendations on Tune

[Synthawk]

I have a 40th anni RX-8 with a midpipe, the K&N filter, and BHR coils. I'm curious if I can use the 92 octane tune that's for a similar set up but high-flow cat + catback. I'm using a catless BHR midpipe with stock exhaust, so I'm hoping that it's relatively the same for a tune. 92 octane is also available here but hard to fine, I'd prefer a 91 octane tune.

[Ugnius @ VersaTune]

You can try that tune, just monitor for knock to see how it's doing.

[Synthawk]

What could I dial back to prevent knock from happening in the first place? I'd prefer to run on the safe side as this isn't a track car.

[Ugnius @ VersaTune]

Ignition timing. I would just flash that tune and drive around logging knock retard among other parameters. Then check if it consistently goes above zero in certain situations. If it does, then dial back ignition timing in that areas. If it doesn't, you're fine with the tune as is.
There will not be any harm caused to your engine by testing that tune, because the ECU detects knock automatically and retards ignition to eliminate it. Difference between 91 and 92 octane is negligible. You should worry more if you want to use 87 with that tune.

[Synthawk]

Roger, thanks. I found reliable 92 so it's really just the high flow + catback versus my stock exhaust with open midpipe that's different now, so I'll go ahead and flash that and see how it works out. Appreciate the feedback.