I'd just go with the FMAX intercooler while you're at it...
Also.. you're gonna need a Cobra MAF if you're looking for 300whp. I would skip the 02 induction manifold since you dont need it to reach 300whp. You'd be better off investing the money into your tranny.
10 to 18 lbs boost is a big range.... btw, what specs are you getting your t3/t4 in?