I want a 1st order 80hz high pass on smallish bookshelf speakers. Does it matter to choose between low end or high end capacitors? Will a cheap Bennec capacitor smear the signal?
In order to create a highpass filter, we will need to know the input impedance of your power amp(s) if you have an integrated unit, it may not be possible. Unless it has both pre-out and amplifier in.
You dont need to go crazy expensive, but in most cases you will only need a tiny cap between your preamp and amp so it's not overly expensive even for goot quality caps.
If you want to create a high pass filter after the power amp, its going to need to be a massive value. (Roughly 250uF for 8ohm or 500uF for 4ohm) and even budget brand polycaps get BIG and expensive, or you need to bundle multiple caps in parallel (2x125uF or 5x 50uF or) neither of which are ideal as they will smear the sound vs a tiny cap between the amp and preamp.
If you know the input impedance of your power amp we can figure out the rest.