Its a cool mod for sure, but not a real efficient mod for the amount spent, with the gains received. You also have to keep in mind that when Tom was doing the swapping round of the superchargers, and having it re tested, that was with a semi basic tune that he only spent like 10 minutes on to get the car to run. If he or somebody sat down, and actually did some work tuning it over the long term, and it sat on a built engine not just swapped on to a stock motor and hope for the best, then you would have one very powerful engine for sure. Such as the case when he was very first running the Whipple on his built 3800 in his Lumina.
These are still accessible for a few who know Tom on a personal level, and it helps hes a local that does not live too far away from me.
If its out of stock at the W-Body store, then its really a no longer produced item, and he should remove that from his site cause its very doubtful he will ever have this restocked, and very doubtful Tom himself is going to make another batch of these, and doubtful he will sell his plans on these to have them reproduced by some one else.
~F~