Jamie
You sound more planned / knowledgable of what you want than most . You know you want to get a little more but not go crazy. Very good first step.
Now, this combo is cool, but if you changed nothing else I'd say you are just a tad high on this C/R for your cam. I would knock it down a pinch (9.5:1) unless I was using S cams... Don't go crazy on the C/R. Make it up with timing and keeping your motor cool (fan) at high revs.
Yes you could twin plug it...that's great...but for the cost of twin plug stick a 70mm crank in it..Now you have a 2.7L...AND make some custom pistons and put some money back in your pocket... A 2.7L is going to do some damage on a 2.5...even a twinplugged one.. This should get your targa to rotate..
Just MHO...