Im still looking around for an sr20det to drop in my 89 240sx, but im still really confused as this is all new and weird to me, why does the s13 red top cost less than the s13 black top? what are the differences between these 2 engines? like i said this is ll very new and confusing to me, so all help would be greatly appreciated. Thanks.

check www.heavythrottle.com i think they have some info on that