I have a NAD 7100 and 3300 and would like to bridge the two using the 7100 to control input but don't have either manuals. There was a prior thread (Bridging NAD 7100 to 2100) that was very helpful but raised two questions for me. The first is what to set my impedance switch to. The person bridging the 7100 to the 2100 was told to set the switch to 4ohms on both units. I'll be using two 8ohm speakers and now I'm not clear if I should set the amps impedance to 4 or 8ohms in bridged mode. I've looked around and it sounds like I should probably switch it to 4 (normal) but still not sure and don't want to damage any equipment. I would also like a brief explanation if possible. The second question. Because the 3300 has LAB IN it was suggested that it be used instead of MAIN IN but there is no switch above the LAB IN as suggested. I plan to set the bridging switch ON on the 3300 but should I leave in jumpers that connect the MAIN IN to the PRE OUT on both left and right? Any information you could give me to help clarify would be greatly appreciated. Thanks.