Those were my twins. . .I split the setup (twins/manifolds) and sold it. . .
Precision doesn't offer the rb26 specific turbine housings, you can purchase the 4828's without their hotside (-$100), but will have to buy the 707160-5 housings and throw them on the 4828's. . .as far as piping goes my plan was to fab up some hard pipes all the way. . .