the b20 might be "just an LS motor bored out to 84mm" but its not the same. i have a bone stock as can be B20 and i run as quick as GSR's with boltons, B16 anything (besides built ones) are a joke, and most LS's are just as slow as the b16's. when i had the LS engine with a mild built head, i was running even to B16's with boltons (hybrids and Si coupes). cost me less than $1000 for the B20, but on the other hand i spent way more than that on parts and labor just for the built LS head and dyno time.