He is contemplating of getting another two units of 4B-SST since the speakers can be tri-amped.
That would be overkill. The Vifa midrange on the EB1i has a very small magnet (240 grams) with low Xmax and FOR SURE the tweeter does not need 200 watts...
I'd suggest your friend looks for much smaller powered amps for the tweeter and midrange - a much lower powered class A might be the ticket.
FWIW: It is definitely worth triamping as you can remove IMD distortion (distortion bleeds from one bandwidth to the next when you use a passive crossover and a single amplifier that is trying to send several AMPS to the Woofer but barely a milli-amp to the tweeter)