I have a 350 and had a loaner 300 during one of my maintenance services. It definitely felt sluggish in comparison, especially after driving them back to back. Also, to me, the throttle response of the 300 wasn't as sharp. In a way, I thought the 250 I drove before I bought my 350 felt more responsive, but it might be because the engine revved more easily. I'd love to see a torque band comparison between the 300 and 350, as down low, the 350 felt much more effortless.

Anyways, it's always best to test drive and see for yourself.

 

IS300:
Attachment 492544

IS350:
Attachment 492545

Crappy MS-Paint Overlay:


Jeff

 

Is that dyno at the crank? At the wheels, it's way lower than those figures. I think 250hp is what a 350 makes.

 

Crank.

Jeff

 

Such a weird torque curve. Why does it dip and go up like that?

 

You see that sometimes, in very "cammy" engines. Obviously designed for best torque at high RPM's, in this case, but having jack-squat off the line is not good in a car with a slushbox tranny.

So, they pulled some design tricks to get something down low, but the end-result has the (frustrating) dip in the mid-range.

There's no such thing as a free lunch, everything is a design compromise, etc, etc.