Building a 318/349 isn’t cheap or easy. Building 318/390 is easy, ordering the kit is pressing a button easy.
Building a 360 or 400+ is dealers choice with the 360 being cheaper, part selection dependent.
A properly built and set up 360 can burn the rubber and be very quick. It is not a slouch.
You don’t need 400+ cubes.
But you want 400+ cubes.
Bottom line, build what you want. Don’t look back. Enjoy!