||Here's the reasons why I am recommending 740s over 555s.
1. The 555s are old style injectors. The 740s are new style.
2. The equivalent of the 555s in the new style are 615s. The 740s don't cost much more, if anything at all these days.
3. 740s + Stock turbos + 3" DPs/TPs/Catback + Ashspec IC Piping + Ashspec Massives + E85 fuel can net you over 500 whp.