i'm having a 2x15 built right now, and i'm torn as to having it made as a 4ohm or 8ohm. i've read the prior posts on this issue, but they don't address my situation. i currently use a kern preamp, and don't intend to change that. my power amp (overkill lab gruppen fp3400) has enough power to run it out of one side (at any impedance). i'm concerned that if i get a 4ohm, i'll be unable to use smaller power amps in 8ohm bridge mode (a 1u amp would be nice). and as far as i know, most power amps are 2 channels. so to get the most out of them with one cab, they would be run bridged at 8 ohms. the other amps i have include an epifani ps1000 (also 500x2 @4ohm, or 1000 bridged @8ohm). it'd be great to buy a micro integrated head, but i'm doubtful i am going to like one enough to replace the kern+power amp. so after all that rambling... if you wanted to use separate power/pre amps, would you go w/ an 8ohm for the same reason, or am i missing something?