I have so far swapped all of the stock Bose with the exception of the rear door speakers. I bought a 12" Kicker in a box with an amp, but am not happy about giving up all the room. I need to fit my bike in the truck and I really don't like the idea of hauling around the extra 40-50 lbs.
Has anyone been able to swap out the bose sub with another open air sub?

 

Plenty of people do this. You'll still have to find a place to locate an aftermarket amp though.

 

is the rear sub amp powered by a 12v source and can i replace it with an aftermarket amp using that same source?

 

Yes, and no. Not enough juice. Best to run a new power source direct from the battery.

 

^THIS

and just get a free air sub, what i hear most doing when replacing the rear sub and just run your amp wires

 

Or even easier, get a Basslink/powered Sub.

 

yes thats the idea, i want to get two 8inch alpine type R subs and mount them where the stock subs are and get an amp to power them and mount them where the sub amp is located so i was wondering if i could just use the stock power line so i would have less work to do.

 

Definitely not, run new wire. And there's no way you can fit two 8's and an amp on the rear deck. The OEM sub amp is mounted on the sub itself!

 

Don't know about the free air sub solution. Didn't see any good options. Only one I found was JL audio sub and just the sub cost over $300 and its also huge, so it might take some trunk space.

 

Hopefully I don't get in trouble for posting links but I was thinking about getting this sub but after research it needs a box too. I, myself need trunk space.

http://www.sundownaudio.com/index.ph...?category_id=3

 

Yeah. I've seen this one before. Better price but not famous brand. I beleive its open air sub so you try it out and let us know

 

^^ That kind of sub is going to need quite a bit of structural reinforcement on the rear deck, as well as a whole lotta dampening to muffle our infamous rattling trunks.

 

The Sa-8 is NOT a free air or IB sub.

 

sounds like the Basslink may be the way to go.

 

If you gonna do sound dampening on rear deck, this guide is for you

http://bestpcreviews.com/car/204-sound-dampening.html