Don't worry Goldie, our little ninja isn't THAT fragile! I think the manufacturer mades these "recommendations" to cover their own ass. So if you push her past 4, you'll still be okay. Just don't redline her whole way home! Hehehe.
I've been out with my baby a few times now. Actually, this Sun did about 225kms. I LOVE her lowered. A few
moments going over craters but I felt SOO much better going over gravel (there was a work site in Kleinberg that we went by) and onto the dirt to park a few times. I lowered her 1 inch in front, 1.5 inch back. Haven't noticed the handling change...actually feels better now that centre of gravity is lower. You can always just do a half inch...should make minimal difference in handling but big difference in comfort. My bum hurts after low rides even with stock seat...I personally wouldn't shave the seat on the new gen Ninjas if you want to travel or ride often.