The 7064 T3 vs the 7163 is not a direct comparison. Too many differences but let me take a stab at this
1) Open Scroll T3 on a SR20. If you are looking for response and transient, you are going to be losing out compared to a 7163
2) The T2 7163 is only offered in 0.85 open scroll housing.
3) The 7163 has the mixed flow turbine wheel and shares the same compressor backing plate of the 6758
4) The 7064 has a 3" inlet (which isn't necessarily a bad thing.....but this somewhat ties into where the low speed surge limit)
5) The results of the 7163 vs the 7064 shows the 7064 losing out to the 7163 in all aspect sans outright balls to the wall HP. Then, the difference was only 20-30 WHP.
The 7064 would be good for an inline 4 with a 2.3 or bigger capacity and a decent flowing head. It was somewhat laggy on the 2.5 boxer Scooby engine (for obvious reasons).
If a mild SR20, I would stick with the 7163. If a worked over SR, I would probably skip the 7064 alltogether and go straight to the 7670.
The 7064 is seemingly the bastard step child of the group.
P.S I have a 7163 for sale currently
