I have a 98 GT. The car is basically stock right now. I bought it about a week ago and so far i have installed the flowmaster american thunder cat-back system. Really liking the sound of it especially since it's still getting louder each day i drive it. Well i noticed a few days ago that my intake is cracked so i ordered a PI intake from summit and a kit to install it on my stock heads. Well just the other day i found a guy selling a set of PI heads complete with cams and valves for $500 shipped to my door. I'm really thinking hard about getting these the throw the heads and intake on my car all at once. What kind of improvement would i expect with the PI heads, intake, and cams? Is it going to be something noticeable right away? Is swapping the heads and intake a backyard weekend job, or something i should send to a shop? Any estimates on cost for the entire swap?