Porsche is pretty good at it, but Bugatti and Zonda are the kings.

Zonda will let you go full out custom if you want, have to have a 6spd manual? No problem.

AMG actually still does custom stuff as well, just for good customers if you ask.

It all comes down to how big of a check you want to write at that level, many manufactures will oblige you well into the 7 figure range if you wish.

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2006 CL500
1969 280SE
2023 Ram 1500
2026 Genesis GV70
2007 Tiara 3200