I think it does match up, but I'm not sure about the HP's. I think to be effective, you'd have to follow through w/good exhaust system. Also, you'd have to have sufficient air coming in the engine. You can't have one w/out the other. Maybe upgrade your air intake system as well. IMO.
The GTX intake manifold is more restrictive than the stock GT one so I wouldn't swap it. The GT head is also better than the GTX head. Kinda odd that the better engine has more restrictive parts on it.
Well, you can get the turbo exhaust manifold from corksport that went on a GTX and throw it on your GT (you'd have to tune it with less boost of course because of the higher compression ratio) and make more power than a GTX.
it depends on if you use the stock ECU or the GTX/GTR ECU. If you use the stock ECU with piggy backs, then stick with the stock manifold and VICS, if running a GTX/GTR or any aftermarket ECU, use the GTX/GTR manifold.