Originally Posted by justpete
As far as I know stage 2 is an on-road tune for an N52 engine with std non-3-stage manifold. Dunno what a stage 3 tune is, don't think there is one really. There are custom tunes with headers, etc. and off-road tunes, iIRC. Andrew's the guy with the right answers though.
"stage 3" would be a 3 stage manifold tune.