I have similar mods as you, also on stock exhaust, and I'm running Stg3 @ default value. I think it's 90%? Everything's running great, pulls hard above 100mph. BTW, I have Rev.I with the 5-29 map.
'08 AW E90 335i
PROcede V5 | BMS DCI | RR DPs | ETS FMIC | FORGE DVs | Stett CP | Vanguard | PSS10