As per title, I'm looking at running two 12 inch subs off my stock head unit but I'm not sure if it can cope :confused: so I was wondering if anyone knew if it can handle it, or would I need to get an aftermarket head unit? Also, if anyone knows, are there any free access holes through the Firewall in an AWD TW magna and also behind the rear seats?

These are the ones I am looking installing:
(http://www.jaycar.com.au/productView.asp?ID=CS2269&form=CAT2&SUBCATID=1027#4)

I run my two sonys off a stock deck in my 380 and haven't got any problems so far but I'm running one of those converter gizmos. I'm not sure if your gonna run one of those but they work great

You will need a line level converter to get the signal to the amps

You will need a line level converter to get the signal to the amps
How much roughly and can I pick them up from an electronics store? (in this case, Jaycar)

About $15..... I bought one last week.. :D

Also, if anyone knows, are there any free access holes through the Firewall in an AWD TW magna and also behind the rear seats?

If you remove the rear bench / base, you will be able to gain access to gaps on each side of the rear seat that you can use to feed wiring straight through to the boot for an amp/s or sub/s. Re: the firewall, there is a rubber grommet directly behind the main centre console to the left of the accelerator pedal that you can expose & pierce using something sharp (with care) to run wiring from the battery to an amp. Note that there are a number of other grommets too (use google to search other threads on this site), or see this post:
http://www.aussiemagna.com/forums/showthread.php?t=81185&highlight=

those active subwoofers have a high level input, so you can feed a speaker level signal into them directly from the rear speaker wiring ;)