bmw stock underseat sub wiring question

[joneal002]

i have a 2008 bmw 528i with hifi 676, my passenger underseat subwoofer is blown and under the driver seat i have a focal sub installed, stock amp doesnt really do it justice, maybe this is a dumb question but since currently im not using passenger sub whta would happen if i ran the passenger connection to driver side and wired them together to help power the focal sub. would this be possible with stock amp or would this cause problems, has anyone ever tried this?