If I was going to redo a 45a I'd make it a...45a!! Nothing wrong with the turbo you have it's a proven bad mother, money would be better spent elsewhere I suspect. If you want to step up to a Billet 70 (or whatever the newest one is called) I'd sell the 45a and buy outright. JMO
Unless it's in need of a rebuild and has hit the wheels I guess.