Stereo in a 99 BMW 328I

Ok so I have a potentially big customer in tomorrow morning and I need to install a head unit in his 99 BMW 328I. He has the 3 way combo in the front and the 2 way set in the rear with a factory amp behind the rear quarter panel on the drivers side. I have 2 questions, are the crossovers passive after the amp or are the built into the factory amp, and second question that I think I already know the answer to is do I have to by pass the amp or can I trigger it and use the speaker outs on the deck to feed the amp, or perhaps make RCA adapters from the factory wires to the preouts on the deck? I thought I had done one of these before but after looking at it, if I did do one I dont remember what the hell I did anymore. Everything is a blur :)double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

I have one coming in next week for a copious amount of bass going into it. It will be a full system, ground up. I did one awhile ago, a 2000 but for the life of me I can't remember what I did, actually now I can, it was new speakers and new 4 channel amp. Now that I think about it more, integrating into it might be a total PITA. Wish I could remember more, that being totally sick and older kinda thing is starting to show....Top Secret, I can tell you but then my wife will kill me.

Ya this car is having a serious upgrade done over the winter. He has a serious carputer he wants me to put in that does entertainment as well as engine management and then he obviously wants glass and the who nine yards. As of right now the damn car only has raido and he wants a deck for a couple months so the guy is laid down for a frigging elcipse 7000 to use for the next couple months. The amount of money people spend is rediculous sometimesdouble-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

I got this car in just over an hour, no one else has a clue on it?double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer