I was looking to amping up my foreman es 450's performance.  Is this what I need 

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110217430361&ih=001&category=43978

? 

If not what's the best pipe, jet combination.... what performance enhancement can I expect.  I'm strictly a mudder and I currently am turning 27" Vampires.  Wouldn't mind more torque.  Thanks for the help