999 sprocket??????

Ok I am sure this has been discussed at length on the site in the past. Bear with me. I have the stock sprocket set on my 999. What size are you guys running , and how big can I go on the rear before I have to replace the chain?
Thanks,

15T front and a 39T rear (with a 520 chain).

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by THEDUCMAN &raquo;</TD></TR><TR><TD CLASS="quote">15T front and a 39T rear (with a 520 chain). </TD></TR></TABLE>

What are the pros and cons with the 520 vs. the 525?

I believe, the largest you can go on the rear would be a 39 t and keep the stock chain.
I am running 14 / 37, the bike has an excellent response with this set up, it is always there we I need it.