sounds like he just swaped the motor, running open header, or he has a leak in the intakemani...
my car sounded just like that when i had a leak and just headers.
sounds exactly like athe guy at the local track with a cammed out VW Rabbit. The thing idles all f**ked up but when he's working it that thign FLIES.
If he turned up his idle it wouldn't sound so bad but that's what a cammed out 4-cylinder engine sounds like folks. I bet it's nearly unusable on the streets but it's awesome on the track.