another option you might want to look into is
www.supersixmotorsports.com
they have a "power package" for the 3.4 (and 3.8 for that matter). basically ported/polished heads, intake manifolds, and new cam. if you want to look into buildin the 3.4 they claim 225hp with that kit on the 3.4. wont get you to the 14s but with some other additions and maybe a spray it could be possible...