T28 ball bearing turbo to T28 journal bearing

[TAP240]

Would it effect my tune negatively if I downgrade from a T28 ball bearing turbo to a T28 journal bearing turbo? I'm sure I'll see some power loss, but will it effect my tune to the point where I'll need a re-tune, or will it just be a matter of the car running slightly richer (meaning a difference in .1-.3 a/f compared to the current tune). Some insight in this situation will be greatly appreciated!

**edit: If I go to a journal bearing turbo, but add a tubular manifold, could that be comparable to a ball bearing turbo with the stock manifold? (Kind of hard to make sense of my question, but I think the principle is implied in there lol)

Thanks