My 1998 328ic is going to get a new amp and sub. I cannot figure out how to remove the sub/amp from the ski pass through location and cannot figure out how to remove the rear seat (backs). I am also concerned that the rear belt tensioners may need to be deactivated prior to removing seat. Any tips?

if you pull up the headrests, the seatback comes right off.

large torx bolts that hold the sub in if i remember correctly. tensioners do not need to be removed.

You remember correctly.... :)

the headrests are a pain to remove. It helps if you have your top down when doing this. Keep us posted on your progress.

Ok. I got the headrests. Got the seat. Got the sub. Where the hell is the amp? Can I presume that the piece of crap sub is a dual voice coil?

the amp on my 94 was right behind the seat back on the passenger side. Not sure if your 98 is different.

more fun on this topic. Anyone have a good idea of where to bury the rca cables (two sets) that will travel from head unit to amps in back? I have a rockford fosgate punch that will power the front and fill. I have an mtx that will power a 10" kicker solobaric sub.

under the carpet, center of car.

forgive my density, but does coming through the center involve a lot of cutting? I don't have the car with me and was buying some rca stuff on way home. Do I need to travel behind the ac controls and behind the computer control center. Finally, if I am bringing some rcas from the head unit to the dash opening (under the onboard computer) for an ipod, do I need to cut anything or is there any type of passthrough. I am concerned that I have too many wires even if there a passthrough with three pre-out rca sets and the ipod rca.

plenty of room behind the ac controls, worst part is getting under the carpet between back of center console and trunk.

won't need to cut anything.

plenty of room behind the ac controls, worst part is getting under the carpet between back of center console and trunk.

won't need to cut anything.

Do I drop the rcas down behind the head, behind the ac controls, behind the onboard and then under the carpet, or do I just get out from behind the head (or ac controls) and get to the carpet first? I am thinking I probably need 16 foot on all my rca pairs.

16ft will be plenty long if you're running cables down the center console. If you haven't purchased your RCAs already, you might want to look at getting a single 4 (or 6) channel cable. Something like these: http://monstercable.com/mpc/productPageMPC.asp?pin=2934&section=three
The cables can run under the rear seat and through to the trunk on the driver's side. There is a factory wiring channel on the driver's side.

My concern wiht that is that it will leave the connections in the head unit area, where space is tight already. Individual pairs will allow me to pull the connection through and under the carpet. You are suggesting run down the center to the trunk, correct?

It's a toss up running individual pairs vs. single cable. I ran a 6 -channel cable down the center console, underneath the carpet on the hump, under rear seat, to drivers side, then through to trunk via factory cable channel. If you are using this path with individual pairs you'll have to do the cable run twice (unless you ziptie two cables together). It was definitely more work to run six plugs at the same time through some of the tight spots but as you can see from the link, the heads of the cable are spaced far enough that you can squeeze one at a time through those tight areas. I really like the idea of a single cable. I also tied a remote cable to the RCA at the same time.

I am at a loss as how to thread the rcas. What plastic portions from the dash and/or climate control/onboard computer area have to be removed? I have also had difficulties getting ALL of the speakers to play through my aftermarket amp. It seems that the wiring diagram I have has some errors. I get the front mids and woofers and the rear woofs, but not the rear tweets or front tweets. I guess they could be blown.

well, what exactly have you tried? have you taken out the sunglass holder and computer?

That's where I was getting stuck. Could not figure out if needed to remove those or remove the dash panels on side of center console. Are these easy to remove and replace

I am at a loss as how to thread the rcas. What plastic portions from the dash and/or climate control/onboard computer area have to be removed? I have also had difficulties getting ALL of the speakers to play through my aftermarket amp. It seems that the wiring diagram I have has some errors. I get the front mids and woofers and the rear woofs, but not the rear tweets or front tweets. I guess they could be blown.

I don't recall the exact path of the RCAs from headunit to the shifter area. I do remember that I removed the OBC, entire center console, climate control, & pocket under OBC. In other words everything between the head unit to back seat was removed. You can then use some semi-rigid wire and fish it down the head unit space towards where the OBC storage pocket is. Probably want to use something more rigid than speaker wire but less rigid than coathanger wire. A piece of 8 guage power cable might do the trick. Just feed it down and feel around to make sure there's enough clearance for your RCAs. Then strap your RCA cable to the feeler cable and pull your RCA through.