Shorty headers do nothing on a stock 5.0 and a CAI doesn't do anything much either. The pulleys will get you about 8hp to the wheels. I'd consider a pro m 80mm maf as your next mod. Only thing to consider is if you plan on a h/c/i combo you will have to have the pro m recalabrated for the bigger injectors that you will need. Or have a chip burned to callibrate the car for the injectors.