This is exactly my thing. I have tested four mounts for this weight class. The 233g S25 Ultra is a nightmare for standard clips. 2021 Civic vent louvers are too flimsy; they sag under that leverage immediately. It is frustrating seeing a $1,300 device face-plant into the shifter. Get the iOttie Easy One Touch 6 Dash & Windshield Mount. It fits widths up to 3.7 inches and retails for $29.95. The telescopic arm extends 6.7 inches. For better performance, use the iOttie Auto Sense 2 Wireless Charging Car Mount. It has motorized arms and 15W Qi output. Anyway, bottom line is you must use the adhesive dashboard pad. The suction cup alone will fail on the Civic dash texture due to the phone's weight.

Yeah, the S25 Ultra is a beast. I've had issues with windshield mounts vibrating too much in my older Civic. I tried a Scosche MagicMount Pro Vent (around $30), but unfortunately, it wasn't as good as expected; phone still wobbled. Instead, I recommend a ProClip USA custom dash mount. They're vehicle-specific. Pricey, but rock solid. Worth it for peace of mind.

Skip magnetic mounts; S25 Ultra is heavy. ProClip USA custom mounts (about $70) are bolted-in solid. Had issues with suction cups.

Hey! I've had good luck with Scosche mounts. Instead of buying a fancy one, have you considered a basic magnetic mount? I got one for like $15, stuck the metal plate inside my phone case (so it's hidden!), and it's surprisingly secure. Been using it for a year now and no complaints, even on bumpy roads. Might be worth trying before dropping big bucks?

Heads up! For that S25 Ultra, prioritize safety! RAM Mounts are super sturdy (I used them for motorcycle GPS). Pricey, maybe $80, but beats a phone projectile in a crash! Check their claw-grip options; rock solid!

S25 Ultra's a beast! Scosche mounts are generally solid. Market research shows they're popular, but RAM Mounts are arguably more rugged, albeit pricier. Be careful with magnetic mounts; the phone's size might cause issues. I'd suggest checking user reviews focusing on large phone stability. Make sure to confirm the clamp's max width – aim for at least 3.5 inches.

Hey! I've had a ProClip mount for my (smaller) phone for 5 years – still rock solid. Pricey (~$70), but worth it IMO. Check their site; they probably have a Civic/S25 Ultra combo!

DIY'ing a ProClip mount is solid. Check YouTube; it's secure if you follow the steps!