I know tons of people have been curious about upgrading the 4 door speakers and 2 tweeters in the C230 Kompressor. I finally went and had it professionally done and the sound is ten times better. I was not looking for a ton of sound so I skipped the sub and I still have the orginal headunit too but the difference in sound is awesome. I was able to replace all 4 door speakes with 6 1/2" speakers and 1" tweeters. I bought all Kenwood Excelon series speakers. I purchased a componet system for the two front 6 1/2 and 1" tweeters with a crossover and seperate 6 1/2 for the two rear. I asked the person who did the install and he said it was not to hard and took about 3 hours and he needed a tool to pop off the clips on the bottom of the door and then uncsrew a couple of screws to get the door panel off. He then had to cut the wire and resplice it to fit my new speakers but he said that was pretty easy. I would still recommend getting a professional install sicne they warrnty it for life and we all know how bitchy Mercedes is with there warrnty. The whole thing cost me with installation $540 and it was so worth it. If any question I will be happy to help.