Fralins are great pickups, no question here. They probably change the sound a bit but both - the original and Fralins are great! Fralins sound pretty Fenderish.
Hey, I have a 83-84 Jazz Sound and I love the sound of it's original pickups. They record super well and they remind me a lot of my former original 60s Fender Jazz Bass sound. The only pickups I would consider to try on my Tokai are Lollars. Or maybe the Lindy Fralins.