That's just so you can run a radiator in the condensor location. They say you can run the factory radiator though, which means you can keep AC if you want. You just end up limited in turbo compressor size and a max of 3" for the downpipe. Any bigger than that, and I don't think you'd be wanting AC anyway.
I'm not baller enough for that manifold. /ubbthreads/images/graemlins/worthy.gif