When is a tune absolutely needed?

Originally Posted by chrischhorn

i understand what you're saying and it makes sense. funny thing is you say maxed out A.k.a. running lean. My car with all my bolt ons was running so pig rich at points hitting 10.9:1 in the afrs. my car was straight up dumping fuel without a tune. my mpg was like 17-18 without the tune. got it leaned out to 13:1 afrs and my mpg is back up to low 20's and the pulls like a beast. Maybe my car is an oddball but without the tune i was running stupid rich and needed to lean it out bad!