The CTS is slightly larger overall. 4.6 inches longer, 2.7 inches wider and .8 inches taller. The CTS has a 6 speed automatic, the G35 has a 5 speed automatic. Taking the product of the dimensions shows that the CTS is about 8% larger than the G35. That would account for about 275 pounds. The transmission would add some more pounds.
Automobile(s): Cadillac CTS Coupe '11 CTS '08 , '07 and '05
Re: Why is the CTS 360 lbs heavier than the G35?
I will let the engineers and the experts give you the correct answer but on the surface it seems to me that its because its a bigger car. 4.6" longer, 2.7" wider and .8"taller. I don't know how much this represents it terms of weight.