Thanx for that, 'How to make a hole' tip! That pushes me off the starting line!

We can all help each other by sharing our steps:

I'll be installing my subwoofer box into my '01 X5 w/ Premium Sound-DSP and NAV & 6-changer CD: I'm going to try to follow Essam's wiring route but I'll post or answer questions as best as I can.

I would like pointers on all the steps that go into the constructing of the subwoofer box.

Besides butt connectors, speaker wire, pipe strapping, sheet metal screws, washers, electrical and duct tape and zip ties and that small 4-pin, box-shaped white plastic input line Alpine MRP M350 amp connector that can be ordered, I'm also going to use a '4 / 8 ga. AGU In-line waterproof Fuse Holder', a 'Hi/Low Impedance Adaptor RCA to line' and a pkg of '24k gold Ring terminals'.....all ordered from ebay.