I did that as well installing the AA BOV. the best way to go about that is to use a box cutter blade and carefully slicing the oem vacuum hose that's fitted on the manifold. After a few slices with a fresh blade, you should be able to pull the hose right off.
So I took it to my friendly dealership, told them what happened, then paid for a new intake manifold and labor. Still kept my warranty as well.
IMO, it's ultimately your car and you can do the brass fitting if you want. But it's a $40k car, so that's why I spent the extra $$ to have it fixed right. You live and you learn, it's just a part of tunning/modding cars.
GL
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'08 AW E90 335i
PROcede V5 | BMS DCI | RR DPs | ETS FMIC | FORGE DVs | Stett CP | Vanguard | PSS10
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