any proven methods on how to shave about 400 pounds off of a stock 2006 GTO???  

According to a couple GTO gurus and upon close inspection by myself, its probably not going to happen. The weight is literally built right into the car. In addition, there is a limited amount of aftermarket parts you can use to drop any weight. If you look at the SLP suspension install we did on our Project 2005 GTO, it took two men to lift one of those rear control arms. The rear differential cradle is no featherweight either, and the same goes for the front K-member. Alot of the body panels seem really thick, and they overlap quite a bit. The Aussies built this thing like a tank from the ground up. One builder told me he removed the entire interior to install a cage and it only took out 100 pounds.

Pretty much your only options are to remove the interior, put in a racing seat, bolt up some lightweight racing wheels, and lightweight brakes....but you probably still won't accrue 400 pounds worth of weight savings. Anything beyond that will require fabrication and/or the need for an unlimited budget.  

try  www.streetcommodores.com.au or www.harrop.com.au just for starters  

try my magnacharger  

I went with two things that saved maybe thirty-five pounds.

A BMR skid plate saved about ten pounds and a fiberglass hood saved about twenty pounds, but all that is moot when seventy pound frame rails are added.

 

I think any GTO-lover, especially hardcore drag racers, will love the new series of tech articles we have coming out starting with the August issue. You won't believe your eyes when you see the sixty-foot times these hefty Goats are capable (with little to no weight reduction).  

I'm pullin' 1.7's and looking to dip into high 10's