Well,
Presumably, like me you found a car that satisfied several needs in different areas. Like any car, improvement can be made in several areas, and each person is free to decide where to put their "points".
While I will most certainly not "rip" anything out of the S4, I surely won't be strapping 20's to it, or adding a 100lbs of stereo equipment. I will be adding power, and handling mods though, to improve upon the platform as I see fit.
You asked, so I provided my candid opinion. I'm not knocking your choices in car mods whatsoever. Do whatever makes you happy.
Play on playa....