With most any car, save perhaps one with forced induction, I wouldn't expect dramatic HP increases with small items like exhausts or intakes.
In the good ole' days, we used to add bigger carbs, intake manifolds, extrude hone them, port tune, change the pistons for higher compression, bore out the engines or stroke them. You could change the valves, camshafts, and have fun, but the BMW engine already runs a high compression, the intake runners are already smooth, nobody is going to touch the engine block, and the double VANOS would make cam changes technologically challenging.
I know this is an expensive mod, but several plunk down over $1K to get clear corner headlights that don't do anything for performance. So at this point, this is the price I pay for a little extra oomph. Btw, I know many are interested in intakes for sound, but this was never my objective. I was actually surprised at how much the sound changed by adding this.
Last edited by ksfrogman; 10-06-2006 at 01:28 AM.