What changes do 990 Super Duke R owners make to improve performance or the ride?

Stock KTM 990 Super Duke R is impressive, but the bike has become a favorite among customizers and performance nutters alike. Many owners aim to unlock more power, make the bike handle better, or get the bike to suit their riding style. They can be anything from an OLT-on part to full engine work. Some riders are looking to improve on the bike’s already potent performance, some want to make it more comfortable for long-distance riding, and some just want to fix what they consider to be shortcomings of the stock setup. The topic of this question is the most popular and the most common modifications done to the 990 Super Duke R and how they affect the riding experience.