I'm sure transmission will need to be addressed next. While i'm not beating on the car with slicks, I can't imagine a stock T5 living trouble-free for years behind 300-350 crank HP. Plus part of me wants to toss a blower on top later down the road.Simple solution would be to just swap your T5 and crossmember out for a T56 and crossmember That sixth gear really does wonders but she is a good bit heavier then the T5
Also I can't remember if you have subframes or not but if you don't, I'd get some mm or steeda full lengths welded up before you park the car for the heads/cam swap.
I've got a shop picked out to install the mm SFC's I have. Just need to set up an appointment take a day off from work and get it done. Right now I have too much going on.