The 163 will be better than the 569, due to the higher carb flange of the 163 [ports are therefore better]...but even better than the 163 is the newly NHRA approved 359 intake, which is even taller at carb flange, and the diffusers on the port floors run side-to-side [towards valves] as opposed to front-to-back like on the 163/569.
But, a full boogie race intake [ie, taller] will definitely have the upper hand over the factory intakes...but the lower profile street/strip offerings [like the Stealth, etc] probably aren't gonna be heads & shoulders above the factory intakes. A lot of it depends on the look/feel you're going for, and ultimately what your performance aspirations are?
I bet our resident induction guru Eric Jackson [Vintage Musclecar] could shed some valuable light on this subject as well...
