Frankly, if you don't know what you are doing, simply don't do it.
I suggest you to simply swap the old caps with some new equivalent ones, i.e. electrolytics bipolar caps, so they can fit in the board. And anyway if you swap a bipolar with a foil cap you will change the ESR, so the new crossover won't work exactly as the old one.
Ralf
It is worth to replace the old caps because they quite surely have changed value over time.
I suggest you to simply swap the old caps with some new equivalent ones, i.e. electrolytics bipolar caps, so they can fit in the board. And anyway if you swap a bipolar with a foil cap you will change the ESR, so the new crossover won't work exactly as the old one.
Ralf
It is worth to replace the old caps because they quite surely have changed value over time.