I've recently acquired a 96 LS400.

After reading about how the wiring of this particular model I feel like I could easily tap into the Factory Headunit signals and run the wiring needed to power and signal to my trusty Sax.100.4. The plan so far is to keep the factory headunit, upgrade the subwoofer, eventually upgrade the front components, use the 4 channel to power the sub and front speakers and use the factory amp to power the rear door speakers that can be faded off if necessary.

I'm not sure what to do about the sub section. This model has a 8" sub mounted in the rear deck, powered by a 30ish watt amplifier. I would like more bass than this factory setup can provide. I'm used to and mostly happy with what I've had in the past which has been an ID10V3 in a ported box at 32HZ and a Tidal Audio 12 in a sealed box. They were both about equal in terms of output with the 12 being a little more robust. Both were powered by the rear channels of the 100.4. I still have both subs.

My thoughts were to conserve trunk space and to install the amp and possibly rig up either the 10 or the 12 in place (probably a mount from below) of the factory 8. I understand that neither sub is appropriate for an IB setup but I was wondering what y'all would think of this setup. The amp would could push 300 watts or so to the sub. I really want to stay away from having a box taking up the space as I typically carry car seats and stuff in the trunk.

Also I'm not sure how to mount this amp. It's a little to big to mount to the sides of the trunk and it would seem like it would fit on the "back wall" of the trunk. The only problem is that there is a gas tank mounted behind the factory panel and I don't know how to mount a board that I could attach the amp too. Does anyone have any ideas on how this is normally done? Pics maybe?

Any help would be appreciated.

John

Similar mounting like this (not mine install but like my car)

I would not mount an aftermarket subwoofer to the rear deck without also adding support. Or else it would rattle like crazy. I would run your Tidal 12" in a sealed enclosure against the rear seat facing the tail lights. You could mount your amplifier on the sub box if needed. This would be a simple install.

A sealed enclosure for one 12" should take up much room in your trunk. It would be easily removable too if needed.