CS5 electrolytic crossover caps. Whoever spotted them was correct, despite the promo stating 'all film caps'. There a few, always shunts to common and always bypassed by the yellow 1uF styrene/ tin foil cap. There is also an iron core inductor in the subwoofer feed. I recall that layout space was the determining factor for that huge board. Outboarding that board would probably be required to allow upgrade of those electrolytics with film caps. Those speakers are 30 years old, nearing their hypothetical service life. None are in sensitive / dangerous positions.