I'm breaking-in my new S2000 which as 300 miles. I noticed however that when I shift my gear from 1st to 2nd (at about 18mph) and 2nd to 3rd (at about 30mph), I can hear and feel a brief grind, "kkrrrkk", on the stick. This problem goes away after driving for 15 mins or so.
Is this normal?

 

well usually after it warms up a bit it gets smoother, but there really should not be any grinding.

 

yup. cold trannys, particularly with low miles, are pretty common to get some of what you're describing on the S2000.

it will likely go away with mileage, or even a tranny fluid change some say fixes it too.