I've used a GT30R with a .63 and .82.
.63 was too small for my 2.3L
.82 made 330kw on BP98. Really good on the street. Actually best turbo imo for the street.
The GT35R I have run with a .82 and 1.06.
.82 was great top end (ran the 10.9 1/4 mile @ 136mph on BP98 fuel - 25psi boost). It was definitely laggier and less responsive against the GT30R. It made 360kw at the wheels when I ran this time.
1.06 I never actually tuned for. It was significantly physically bigger and would have given it much more top end. It lost the turbo spool at idle but I'm sure I would have made a lot more power! I believe it would have gotten me close to the 400kw's on 98 and more with E85.
The other in between sizes are not T3 flanged so I can't comment.
If you need rods and other parts, I'm actually just about to advertise some in the FS section.
I'm sure your stock engine could take the punishment on low boost.... mind you, these turbo's like 25+ psi.
Ask Brisvr4 how he gets his stock block VR4 running so well!