Start with your basics of engine operation.. you need fuel, compression and spark... pull out a spark plug, and attach the coil to it.. point the spark plug away from anything metal, but don't hold it.. turn the car over and see if the spark plug is creating a blue arc across it... IF IT IS, find your main fuel line that feeds fuel to the engine from the tank, and crack it (should be a line connection type fitting) and see if fuel comes out when you crank it.. again be smart, don't spray fuel all over anything that ignites.. if you have fuel and spark, you gotta start doin compression tests, and making sure your valves are opening and closing when they should...
My best guess since you say you pinched your fuel injector wires, is that it'll be a fuel issue.. if you can, pull off each injector wire, and see what voltage you have at the connectors with the key on, should be 12v I think...? also, ohm your injectors,, they should sit about 14ohms....
Hope this is a start for you.. if anyone sees any discrepancies, please correct me... I'm not a bmw mechanic, Im an audi mechanic lol