Yeah, I almost always use some sort of LSP-based approach on black plastic and even exterior rubber, works super for me.
Right off-hand the only such surfaces I can think of where this doesn't work on are the foglight covers and sideview mirror rubber of my '85 XJS. And I do use wax, usually Souveran, on most of that vehicle's exterior plastic/rubber trim (been working well for decades, those surfaces are still like new).
845 works *very* well, it's what I used on the plastic and rubber trim of my Blazer, and the Volvo wagon before that. I also used it on the Yukon before switching to FK1000P (most of the trim) and KSG (the rest of it, including the rubber facings on the runningboards and rear step bumper).
Be careful using FK1000P for this, any excess results in staining. Not a real problem if you buff thoroughly.
Yeah, 845 can start looking crappy when it needs redone, but that takes months. It never looks quite as bad as such surfaces do when they've been treated with 476S and need redone (yeah, 476S, used that on the Volvo for a few years; no it didn't stain when I did it right).
Yeah, I used the regular Klasse twins on the Yukon's textured rubber facings, started doing that on the MPV's rubber back bumper cover pad. Works fine. I generally use the twins on *all* exterior plastic and rubber, textured or not, but you do have to watch you buff the excess off thoroughly (try the W-O-W-O approach). Not nearly as finicky as FK1000P though.
And yeah, the Sonus Acrylic Glanz spritz is a quick and easy way to refresh those surfaces. But I usually just give 'em a bit of FK425/etc. after each wash, along with the rest of the vehicle.
