LOL. Thats where alot of issues start is where people who buy a car like this and then try and upgrade the system in it. Its Mercedes not a Honda Civic. It comes with a Bose or Harmon Kardon System. The best money can buy. As far as upgrading Mercedes you can take a run of the mill E320 and very very easily do performance upgrades. I know a guy with a E320 with a Turbo in it. He is pushing about 400BHP from the stock M104 Motor and a no need to change the transmission since it is a 722.6. A widly used transmission in some of the worlds fastest cars. The thing is that its not worth the money putting into a E320 becasue its not considered the performance model. I mean its far from slow. Take my 2002 E320. 0-60 in 6.6 seconds. 145Mph top speed. Not a slow car when you consider it weights like 3,500LBS seats 5 very comfy and gets about 30mpg on the highway. I have recorded 34mpg with it at most. As far as your friend with his light bulbs. He must have the Xeons lights if there $70. But any car with those will cost alot of money doesnt matter if its Mercedes or GMC. As far as the tires thats BS. You can buy any kind of tire for any car. What you need to do is find what is best for the car and conditions. Sounds like he has a lack of knowledge about his car. This will end up costing alot in the future. Need to be educated on what you drive. And dont take any car to a dealer. $tealer$hip