ive been rideing alot of muni/ downhill lately and whenever I go to make a turn or slow down to do setup hops for a drop i lose my tire grip how do i reduce this?
get a new,better tire 
what would you sugest it has to fit on my 20 in lx
Check your LBS, go and ask them for the biggest grippiest tire that will ft your uni, so bring your uni with ya =p, I think Kenda makes a really grippy tire that will fit too.