I have a Diamondback Sorrento as a commuter. A $199 bike in near perfect condition with an Acera X drivetrain and a solid chromo steel frame and city slicker tires. Good is good, but better is better, and perfect is what I strive for. I would like to go to a Deore LX or XT drivetrain one piece at a time starting with the rear derailler. Is it going to be any smoother\better. Could I upgrade it enough for under $150 to make a noticeable difference. Or should I save up for a new bike already equipped. I'm thinking of new pedals too, I heard some creaking under extreme power up a hill yesterday.