yeah they helped my wheel hop a lot in the winter. it was bad before with the stock pulley and stock exhaust in the summer-fall, added MM IRS bushings it got slightly better, but still hopped some (never hopped on drag radials though) added H&R Race springs and hop was gone, except for really cold temps (<35*). then i added the 2.75 pulley and it was hopping in any temp (20*-60*), had the MM full length subs welded in on tuesday, temps have been in the 20s all week, and it just spings 1st and 2nd with no hop at all.