Just trying to decide. Salesman says Marantz sound better but I see 45TX has more options: - 7 amps - more crossover options - MCACC - THX I downloaded manual from Pioneer web site but I do not understund how to bi-amp front L & R when using "regular" 5.1 channel setup. Also can anybody talk about the RS232 connector? Does it exists or not? In case the answer is YES is it for future firmware upgrade (like the one in Marantz 7300) ? Thanks in advance J.G.