gsxr 600

I need some help on lowering my bike. I go online and try to look for options however, I don't know which ones to choose. Some lowering kits come with 3 parts others come with 2. Could someone please direct me on which one to buy. I don't know if this helps or not but, I am 5'4" and my toes are...

After I go up pass 8k rpms my bike starts jerking...just started doing this right after I put a full tank of gas. Anyone have an idea of why this might be?

Looking to put a slip-on on my 05 gsxr600. I'm looking at the two bros vale m2 or the yoshimura rs3..any suggestions as to which of these is better or any other slip-ons that are a different model??