Most people probably carry larger/heavier loads when going on vacation, than we add in weight with audio gear..
If your car is dragging its rear-end on the pavement, then suspension upgrades are necessary..
Well, in my Trans-Am, in regards to just the hatch area, I added the following:
- 10lb nitrous bottle
- Rear Battery
- Isolator relay
- Brain for the IVA-D900 headunit
- H701 Processor
- Alpine Nav unit
- 3/4" MDF sub box for 2 12" subs
- 2 TCSounds TC2+ drivers
- 1 gal air tank
- Air valve
- Air compressor
- Airbag control system
- Alpine XM tuner
- Alpine alarm pager unit
- Alpine Nav guide interface
- 4 ESX Quantum amplifiers (not small and not light, probably over 80lbs for these alone)
- 4 ESX Quantum Balanced Line Drivers w/18ft cables
- 30-40lbs of sound deadening mat/sludge/closed cell foam
- 10-15lb mounting board
and over 40lbs of wiring/fuse holders/distro blocks/amp mounts/brackets/panels
So, yeah, I have a ton of weight back there. I run the Eibach Pro-Kit lowering springs, KYB AGX adjustable shocks as well as helper spring airbags in back. The airbags allow me to have passengers in the rear seats, or to siffen up the suspension when I want more grip for launching the car (racing)... I have probably in excess of an additional 200-250lbs above and behind the rear axle...
The rest of the car is no lightweight either, with the supercharger/aftercooler systems, fuel system w/cooler, nitrous system, additional motor electronics, sound deadening throughout, heavy duty racing suspension, Dana 60 rear end, etc, etc... Car weighs probably over 4100lbs...