Upgrading the stereo on my soon-to-be-purchased Prius will be one of the first things I do. I'll probably be getting JBL + Nav. I've been reading through about a zillion threads in this forum and I'm still not clear on a few issues. I will definitely be putting in a subwoofer (with amp), probably upgrading the front speakers, and maybe installing a new amp for the fronts only (normally I get a 4-channel and use two channels for the sub, two for the fronts, and leave the rears as-is). Best-case scenario would seem to be to connect something like a CleanSweep SSI to the front channels, to create relatively flat front L and R channels, then feed those to a 4-channel amp with built-in crossover. Feed the high-pass (or all-pass) to the fronts, and replace the fronts with standard component separates. Feed the low-pass to a sub. Is this a reasonable approach? Will the summing the front low and mid/hi channels from the JBL amp yield L/R channels that are anywhere near flat, or do I really need to feed it through a DSP? I'm trying to keep it simple; the summer seems unavoidable but I don't particularaly want to go the DSP route unless it's really necessary. Have I overlooked anything? Failing the above scenario, I wouldn't even know how to upgrade the front speakers, given the existing bi-amped design for the front which is (I presume) crossed over too low for standard 2-way separates. If I went the sub-only route, could I just tap the sub off the front woofer channels? I prefer to use the front channels for my subs because it works much better when trying to manage the front/rear fade. As always, these factory systems make this more complicated than it needs to be. Oh well!