I heard you can make a 00'-02' ktm 520sx a 6 speed?

[ltzrid3r400]

I'm looking into picking up a ktm 520sx from my buddy, and it's only a 4 speed that would be fine for trails and everything, but i was thinking down the road, checking with the DMV in my state (CT) and seeing about making it street legal, and if i did that i think i would want to add more top end to it, someone said something about them making a kit to make it a 6 speed? i'm not sure. but any help of where i could find it, or if it even exists, would be great...alright thanks