Well I just got my new pretty OS Vspec installed yesterday, before I went to bed I read through the whole manual, and in multiple places it says OS recommends 20% nitro for this engine. What confuses me is that I've read online that the engine is shimmed for 30%.

Should I go with OS's recommendation or what I've heard elsewhere? How much of a performance increase am I gonna get running a 10% higher nitro mix anyway?

More pictures - http://flickr.com/photos/revtothered...7600161423180/