Maybe check out www.sounddomain.com
since there should be a shitload of audio enthusiasts, perhaps check our their Celica section or see what other people are running.
I kind of want a custom box too, but I'm still not sure if I am going for show or go, but for the time being I do have a couple of 10"s in the back, because loud music is a must!
It's pretty much nothing but here is my stuff.
amp (attached to other side of sub box)neons
(stuck two images together, one tube in each footwell)