According to supraforums, the r154 currently has 2 members putting 7xxrwhp on them, if i recall correctly. Every one knows its just a ticking time bomb. As far as clutchs that will hold the power for the r154, ogura(ORC) makes up to a quad-plate clutch. They also say that the soarer r154 are a bit stronger than the US spec mkIII turbo r154's. Something about the larger something. I forgot. I personally went with the getrag, but then again, i got it for a steal. Best of luck with your project.