if your in the u.s. i'd go for anyone that sells CDI brand - iboats has a store - marinemanifold.com is a good one i use in canada . ebay has some marine stores that sell parts - i've used them without any problems .
genuine merc parts? they are made by an outside company stamped with mercury's logo and resold at double the price . just like the big auto makers they have pensions and warranty programs to pay for and theres have got out of hand also . contrary to popular belief mercury doesn't own an oil refinery either .