If you said you for sure ordered the e92 PE exhaust, and they shipped you the wrong one(e90), then YOU should hold the dealership responsible, period. Make them responsible for everything that went wrong from installing the wrong type of exhaust on the wrong car.
Just bc you had work done at the dealership, doesn't mean they know what they're doing or talking about, a lot of times it's quite the opposite.....sad but true!
'08 AW E90 335i
PROcede V5 | BMS DCI | RR DPs | ETS FMIC | FORGE DVs | Stett CP | Vanguard | PSS10