+1 on the V6, the 4 cylinders tend to have problems early on. If you decide on the W203, take a look at the link below to our site's DIY tech articles. These guides will save you a lot of headaches and $$ if you're doing the work yourself. Please let us know if you have any questions!

Mercedes-Benz C-Class W203 (2000-2007) Technical Articles – C320 E320 ML320 CLK320 SLK320 – Pelican Parts