Photos of the problem areas would really help.
But offhand, I'd say skip the Klasse. Using that and Wolfgang sealant is redundant. Having used both, I prefer Wolfgang. Klasse is ok at hiding swirls but eventually it wears off and you'll see the same swirls. The better way to go is to get rid of the swirls entirely. A Maserati deserves that
My experience has been that IP2000 won't finish well enough to go straight to a sealant. Klasse would hide the marks left by it, but that's a bandaid fix. You'd want to follow it up with a polish like Menzerna SF4000.
What color is the car? Does it have metal flake? Fuzion would probably be a good choice, but depending on the paint there might be other options to consider.
Without more information, I'd suggest:
stripping shampoo
Clay bar
Menzerna FG400 or Wolfgang Uber compound (if needed)
Menzerna SF4000 or Wolfgang Finishing Glaze
Wolfgang Deep Gloss Paint Sealant
Wolfgang Fuzion
