Many years ago I owned a set of the System 3's. The electrostatic element was quite good and was one of the few speakers that created a stable image that did not move as you walked between the speakers. No matter where you sat, so long as you were between the speakers, the imaging was the same, no sweet spot. The woofers were unfortunately not very good and did not mate well with the electrostatic panels. The crossover also left something to be desired. If you refurbish, suggest that you remove the woofers and crossover and substitute an external crossover and woofers. Beverage had a nice crossover which the son may still be able to provide. The combination of an external active crossover and proper woofers might yield a world class system. Even returned to stock, they should be a nice improvement over the ML's.