Okay, here's a quick update. I have ordered two pairs of Hertz XL165 component speakers for the IS350. These are the Hi-Energy series and have great SQ characteristics. They will be here next week, as will the speaker adapters that I got off a dude on Ebay. As for the adapters, two pair are for fitment of the aftermarket 6.5s in the funky OEM three hole mounting formation. The other pair are to mount the tweets that come with the component set. From what I can tell, the tweet adapters are supposed to allow you to run a tweet where the factory mid speakers are. Asked the seller, but never got a response. I order them anyway and will figure that part out when they get here.
I also have a JL Audio CleanSweep signal processor, which I may or may not install later (just doing the speaker upgrade for now). My new issue, is the wiring configuration that exists in the factory set up........ In the rear doors, the wiring schematic shows that there is one signal for each door, coming from the amp. That signal is split at each door, with one runnning just to the woofer and the other runnning both the mid and the tweet. If I were to eliminate the factory tweets in the rear doors, this would be a simple deal. I would simply take that single signal and run it into the crossover for the Hertz speakers, and then wire the outbound to the woofer and the tweeter (leaving the OEM tweeters in place, but without signal). The front doors are the isue, as there are separate signals for each door (two per door). One goes just to the woofer, and the other goes to the mid and the tweet. The output of the amp is a total of 6 lines, one for each rear door and two for each front door. My concern with this is whether there is a set crossover point in the factory amp, which sends only lower frequencies to the woofers in the front doors and higher frequencies to the mid and the tweet. If I utilized the woofer signal for the Hertz speakers, there would be little if any mid and high frequency signals to send to the Hertz tweeters. If I use the factory signal to the OEM mid and tweet, this may result in little if any low frequency signal going to the Hertz woofers.
Put simply, anyone ever installed component speakers in one of these, and if so, which line did you use for the front doors? Worst case scenario, I can connect to each and go with whichever gives the best sound quality. Definitely want to get the best sound possible, without running the processor if I don't have to.
Sorry for the length, and hope it isn't confusing. I am confident that it will make perfect sense to those who have tackled this before.
Thanks,
Dean