The cams are a barely noticable effect and will help you drop 2/10s thats it. If you are going for power do turbo or leave the car alone. Nothing else is worth it.
A turbo will be a good upgrade but you will void the warrenty, dealerships will refuse service and even minor problems become a big headache. Oil, water and fule leaks are the main ones but a boost or intake leak are the guarenteed pain in the ass.
Another thing to remeber is that even wiht a turb your car will only approach the power of others cars stock. You will not easily outrun a WRX, RSX types S a GTI 1.8T or alot of other compacts. The tubo needs to be for you alone and not to show off to others as you will be chumped.
Also expect atleast $1000 in extras. You will need a new clutch, the stock one will slip even with modest boost and a exhuast is a definite/ Additionaly you will want a few guages aswell and you have to pay for accuracy.