My friends 00, just put down 242/286 with just a catback, CAI, and TB. My dads similar 5.0 with catback, pulleys, and filter made 212/276. Tell me 30 more hp and 10 more tq (not to mention a better curve) isnt an improvement. Also remember the 96-98 cars were dogs, so the jump to the PI heads was a big increase. Also the 4V cars make great power, and even the 05+. My brothers bone stocker did 265/286 and another one with an axleback, CAI and tune did 277/296. I would say thats improving.