which brand ball bearing turbos? If they're HKS GT2530's, you can ONLY get the center sections through HKS and HKS vendors (but it's been discovered that you can use a GT28RS CHRA and swap the wheels over to save a LOT of money). If they're Garrett GT28's or some other common Garrett turbo, you can get them through anyone who sells Garrett turbos. I'd recommend calling local turbo service shops (not speed shops, there are shops who specifically work on turbos for trucks and the like) and tell them what you need. They'll probably be able to get it for you.