Greetings- I 've been using a JBL M552 electronic crossover for biamping my 4343s for about the last two years and have been quite pleased with the results. However, never wanting to leave things as they are, I've been considering switching to a JBL/UREI 525 crossover to replace the M552. What are your thoughts on this unit? , would it be an upgrade or should I just leave things as they are? I'd appreciate your feedback, Thanks very much, Paul ps- As I don't own a JBL/UREI 525 at the moment, are there any available here on the forum?, and if not, what should I expect to pay for one? Thanks again, wpod