Awesome! Well I don't think ATI does the A343F transmission I would recommend you send it to ATF Speed in Florida. They are the ones that just set the 1/4 mile record with the A340. They have it holding high 800hp in a Supra. They have new billet parts that should work in the A343F.
For head work I would look at Brooks Elliott Cylinder Head in Austin. I would at the very least go to a stiffer valve spring as you will get some valve float at those boost levels. Depending on how much you want to spend, also up size the valves. The head is going to be your best bet to make power but it is also the part you could spend the most money on. Very easy to add cams, hand porting, etc but I think the stock head with larger valves will probably flow well enough.
ATF Speed.com
Brooks Elliott Cylinder Heads