So what kinda noises do the exhaust manifolds make when they get the infamous cracks in them? I suspect i have a least one of mine leaking if not both. I been getting a whistle sound as a vacuum leak would make but i don't have a vacuum leak. Under hard throttle or high free reving is when i hear the whistling sound. I also hear some air sucking sound as the intake does but this is not my intake. Any thoughts people?? I've not even got 60,000 on my '04 so i should still be alright on the 80,000 mile Emissions warranty. If just one is leaking i like to try and con them into changing both. I've got a good dealer thats always treated me pretty fair.