The blacktop has lighter internals which happen to be also weaker, but it's a bit more rapidly. No harm if you're not accomplishing any huge mods, but any compelled induction and you'll be needing to uprate the blacktops internals. The high res injectors have a different clip to low res https://4age20vblacktopforsale61482.eedblog.com/26819885/the-4age-20v-diaries