C230 Kompressor or C320?

Ok my dad is looking at some of these c class benzes and we dont know what to get. They have an 05 c230 Kompressor that is really nice with 15k miles on it. It was a dealer loaner car and I'm sure has been well maintained. They have many c320's to choose from but my dad said he wasnt very impressed with the power. I think gas mileage would be about the same for both cars(if I'm wrong tell me lol). Is the 230 Kompressor actually lighter? I heard that it was but have no clue. What would you choose?? Interior wise they seem the same other than the 05 is gonna be pretty emaculate inside.

I have a 2005 C230 Kompressor. 37K miles. First 30K miles averaged 25.3 MPG per the trip computer. On the freeway, it gets 31 to 33 MPG. Today I drove a 2007 C230 with the new smaller V6. It seems that gas mileage on a test drive was 18 to 24 MPG. Not nearly as good.