Questions: Ignition Advancer for a ZX6R 2002

[boomer87]

hey guys, sorry for asking more questions...but....... im thinking of buying a ignition advancer for my zx6r

after looking around on the net i think understand the basics of a Ignition Advancer. advancers the spark so it fires closer to TDC (Top Dead Centre) and allows a snappier, crisper feel when accelerating.

Factory Pro does one for '02 zx6r for US$59.95 +$16postage, which at todays exchange rate: AU$86.85 in my hands.
webpage is http://www.factorypro.com/Prod_Pages/prodk89.html (Ignition Advancer one third down page)

My bike is 2002 ZX6R with Yoshi exhaust system, K & N air filter (bought it like this, so dont know if its been tuned with exhaust & filter on [cracks and pop alot under engine breaking so assuming not])

my questions are:

1. Will advancing the spark cause problems like overheating, knocking, excessive engine wear or other bad things that will hurt my baby??
2. Will the exhaust and air filter make any difference with this kind of mod?
3. Is Factory Pro the best place to buy one for us here in Australia?
4. What degree should I buy for my bike (+2 +4 +6) and looking at the Factory Pro page how do I specify which degree i want to buy from them?