schumajb- Welcome to Autopia!
Congrats on the new car (I had a WRX myself a while back).
Black is tricky, but only because it shows everything. If you find it's getting marred up, try to figure out what you're doing wrong. FWIW, I can't really wash without marring unless I use a foamgun. Money well-spent IMO.
Even new cars can need polished if somebody's marred them. My WRX had been washed before I got it and yep, they instilled some tiny scratches that I had to polish out.
Claying: claying so aggressively that you remove the LSP is *IMO* too aggressive. I spot-clay at every wash, have since the early '90s, and gentle claying doesn't remove an appreciable amount of LSP. Claying too aggressively can mar the paint, so try to be gentle.
On the vehicles I use KSG on (I used it on my WRX), I can generally just clay gently with Sonus green Ultra Fine clay and apply more KSG, and I can do this for a long, long time. Don't need to redo it from scratch (no pun intended but...) more than once a year if that. What eventually happens is that the paint gets marred, so you have to polish out the scratches, so *that's* a good time to start over (see, it kinda *is* starting from "scratch"
).
I don't use terry for much of anything. I apply AIO with either foam or MF. I apply KSG with foam and I don't dampen it first. If you can clearly see the KSG on thep paint then you're using way too much. If it's hard to buff off then a) you used too much and b) try fogging the surface of the paint with yoru breath while you buff it off. FWIW I probably used less than 1/2 an ounce of KSG to do my WRX (that's not a typo, I did mean "less than one half of an ounce" ).
Yeah, you can use the AIO to clean everything (including the KSG) off, but wait and see if you can get away with just doing that, I bet you'll find you need to polish out some marring. That's not intended as a put-down...washing without marring the paint is *hard*. It's a near-obsession with me and I work *very* hard at it, but sometimes I still get marring (but not too often any more
).
Speaking of washing, you might find the NXT to be a bit harsh on the KSG. I use Griot's Car Wash, which doesn't seem to strip the KSG at all. Gold Class would be an OTC option.
Oh, almost forgot- I used the Klasse twins on my WRX's black plastic exterior trim. Worked great!
; keyword is: should, aggressive claying should be able to remove your LSP for the most part.