The tubular will not necessarily get you gains in terms of peak numbers, at least on the stock turbo. It will give you some nice gains throughout though. Here's an example:

*note: The gains also include any gained from the o2/dp and Intake mani*



Up to you on whether you think those gains are worth it though.

 

Glad to see your doing research now, after you bought the manifold. I'm sure you will still see minimul gain on the stock turbo with the new manifold. If anything, spend 300 on a alky injection kit and leave the stock 02housing on. I highly doubt you will notice anything over your current exhaust setup by switching up.