I have a 2011 busa with a 330 osd and stretched 6 inches. I tried to tighten the rear suspension on it but when I ride 2 up with my wife on the back it sits to low and I don't want it to rub. Has anyone replaced there rear spring with a heavier spring without rebuilding the shock? and if so how did it ride and did you have any problems occur. I was planning on goin with a heavier spring from Racetech.