The upgrades on my own 990 were done in two stages. The mirrors, intake system, high fender kit, stage III emissions removal, doghouse storage box and ECU reprogramming comprised the first stage of modifications. All was done in my shop with my own two hands, exactly how a mail order customer would have to do it. On a mechanical difficulty scale of 1-10, nothing on this list would rate over a 6 other than one part of the Stage III Emissions Kit. Just to give you an idea of my mechanical ability, changing a two stroke top end is the most involved thing I would tackle solo and a four stroke valve adjustment required professional, hands on guidance and literally took all day. The forward cylinder block off plate is very difficult to install, not because of mechanical complexity, only because of the cramped space in that area, the only part that received a “6” rating. Reprogramming the ECU seems to strike fear into many, but the free Tune ECU software and watching Chris’ instructional video on his site vanquished any fears and the process went smoothly.