I am on the market for a "S", either S 320 cdi or S350.

How loud is S320 diesel?

How is the performance of S350 compared to S320?

can't comment. we do not have s320s here.
Wish they did.

I don't think you have 350-model either.

The 320 CDI cannot be noticed while driving except a faint turbo whistle at full throttle and you can hear the engine idle while a gasser hardly can be heard at idle. The noise outside is still a lot higher than with gassers even if multiple injection CDIs have a lot lower noise than older diesels.

You really have to test drive both if noise and acceleration are the most important factors for your decision. Acceleration is almost the same (see reported figures).

Usually diesel is for those who want fuel economy.

i doubt anybody buys that type of S model for performance reasons

Yes, you are right no s350 either. but my understanding is the s350 engine is the hybrid engine in usa as s400 model.

I haven't driven them either, so really can't comment.
Yeap, most who buy these do not buy for performance, but Americans love big engines. Broom Broom...

Some could buy an S350 for performance over the S280 or S300.

I was referring to the fuel economy between the 320 CDI versus the 350 gasser.

I have driven the S350 prior to buying S500 and I can say I liked the S350 a lot, it revs nicely, perfect sounding engine, almost whispering on the outside. I say get it.

Hi, I own the s320 diesel i can tell you that the diesel isn't loud. It is very quite for a diesel car. The performance is good. I think the s320 and the s350 are almost the same. The s320 is a little bit louder but inside the car you wouldn't hear if it is a diesel.
I bought it because the fuel consumption is lesser than the s350. And the performance is good enough for me. But do you want a good performance car than i rather look to the s420 diesel or s500-600 car. I prefer the diesel car because of they can handle high milage