Red Wine Audio only works on two models, see below. I understand the results are worth it, but you'll be giving up the headphone output.
"Please Note -- The iMod is only offered for the 4th Generation and 5th/5.5 Generation iPods, as they contain the high-quality internal Wolfson dac chip that makes doing the iMod worthwhile.
We DO NOT and WILL NOT modify any of the other iPods, including the new 6th Generation iPod Classic, iPhone, iTouch, or any of the Nanos."