he painful mediocrity of the Sentra suggests that the days of truly great small Nissans might be gone. The 1.8-liter four-cylinder makes a lethargic 130 hp and comes standard with a six-speed manual; a CVT is optional. For more power, the SR Turbo makes 188 hp, gets bigger front brakes, and has a firmer suspension. It offers the same transmission choices as the base model, although both manual and CVT are beefed up for performance duty. The Turbo Premium package adds leather and Bose audio.