Almost all of the aftermarket exhaust manufacturers require a change of powersteering/alternator bracket, including the last pair of Stainless Marine exhaust I recently installed on a Baja Bandit. I am not sure about SMs' efi/serpentine belt bracket, but the polished bracket from Revolution Marine looks kickin.
The Revolution Marine exhaust do indeed run aluminum risers, but if you look at the transition of exhaust flow from the manifold to the riser you notice the largr rectangle opening of the Revolution Marine riser is more "port matched" to the manifold. The other brands with stainless risers go from a square or rectangle opening of the manifold to a much smaller round opening of the riser pipe. Still better than stock cast iron but not exactly a smooth transition where exhaust flow is concerned. While I agree the stainless riser pipes look cool, most of my customers want the performance. Besides, we've sold and installed a number of Revolution Marine manifolds using polished stainless tubing in place of the black exhaust tubing which makes a huge difference in looks.