Was faced with the same dilemma (well not the diesel part since we can't get that here in the states). Was pretty set on the 3.5 - car feels light and moves nicely.

Then, I started a 50i up. Thought it had an aftermarket exhaust it sounded so good. Turns out that's stock - the pure V8 sound upon starting an accelerating.

I agree, the 35 felt more nimble. I agree the 35 used less gas. I agree the 35 was more than enough power for this car.

However. in the end, the sound and the serious torque that comes out of the V8 was just too much to pass up.