When erected my penis bend downwards about 30-40 degree from the middle of the shaft. will this affect my sexual performance?

Only1way2findout: Sounds like you're describing Peyronie's disease (http://www.mayoclinic.org/diseases-conditions/peyronies-disease/basics/definition/con-20028765) for which there is now a medical/pharmacologic option, Xiaflex (collagenase clostridium histolyticum) (http://www.fda.gov/newsevents/newsroom/pressannouncements/ucm377849.htm). Only you can tell whether or not Peyronie's will affect your performance.