You did not mention what brands are currently in the speakers now. The type of sound, equipment, and music that you prefer is critical in making recommendations. One thing I can recommend to you... Immediately replace your resistor with a 10 watt wire wound resistor from Ohmite(or equivalent). You will notice that grunge, grain, grit, spit, splashiness, shrillness, and irritability will be much improved. As for the capacitor, this is a relatively low voltage unit(though not for OEM) you described. Who makes it? And is it electrolytic(would seem so from the voltage rating)? The related components, desired sound, and musical tastes will play a big factor in what I recommend to you there. I can say that for this capacitor(since it is a low value), you should be using at least a Wonder Cap. Which is very likely better than what you currently have. Depending on how you answer my above question, I might recommend something much better(film and foil).