Yep, the relatively cheap Jaycar subbies Mick had put in as replacements for his shelf ones really rock! See
http://www.ls1.com.au/forum/showthread.php?169281 though obviously you can't hear it, but believe me the bass is quite decent!! Almost had me wondering whether I'd gone over the top paying just over $1k installed by a local whizz for my (now relatively) new setup, but that did include a decent 10" sub in a box in the boot, an RRP ~ $600 amp and front splits.
PS Mick's subs were Jaycar Response 8".