You only have to worry about detonation if you're running to much boost...or not enough fuel. 6 PSI is perfectly streetable. The reflash is not necessary but certainly makes an honest improvement. Read up on various posts about boosted Lancers.

 

how much hp increase do people usually see with 5-6 lbs of boost and how reliable is it long term?

 

i think i heard 10 hp per psi right? so 50 - 60 horses i belive. 5-6 psi is pretty reliable.

 

i know its pretty reliable but what about for 60k miles or more down the road

 

not sure no one has gone that far. only time will tell.