Just had a kenwood installed in my '81 380sl at Best Buy. Not knowing a single thing about stereos, I thought one of you guys could fill me in...First of all, I thought it was kind of ridiculous that you spend 500 bucks and they charge an extra 150 bucks to install it! Plus, since the speakers I want in the back are bigger than the ones in it, I would have to cut the holes myself because they won't. Anyway, I opted to just pay $50 to have the unit put in the dash and I would do the rest. Had a appointment for 10:00. Show up, they look at it and say that the unit in it (stock Becker) is pre-amped (?) so they would have to bypass it and it would cost me $160.00! It took them 4 1/2 hours to get it done! My question is, was this pre-amp bypass necessary? Because the people that worked on my car were very unprofessional and if I got shafted, I intend to raise a BIG stink! Thanks in advance for your help!