The location is prime. Right on the water in Stamford, with floor-to-ceiling windows overlooking a harbor filled with pleasure boats. Comfortable, contemporary, and sophisticated, Prime serves an updated American surf and turf menu. Start with sushi, and end with steak. That’s what we did. Prime, which opened 2 years ago, wasn’t on my radar, until I was invited to dinner there by Carolyn Izzo of CIIS.  It’s one of the 8 restaurants in the Bohlsen Restaurant Group, which runs another Prime across Long Island Sound in Huntington, N.Y. The intriguing avocado-wrapped Green Lotus revealed an interior of spicy tuna, lump crab, and Asian pear. The Stamford Landing roll wrapped tuna over shrimp tempura and avocado. For those who avoid sushi, a starter of prosciutto and caramelized figs, with almonds and goat cheese, drizzled with balsamic glaze, was sweet and salty. Prime lived up to its name with this 21-day aged USA Prime porterhouse steak for two. It had a good char on the outside, and was pink, well-marbled, tender and full of beefy flavor.  It …