I just ran into this issue.
One of the issues I ran into was, if I simply deleted the bracket, I needed a shorter or fully threaded stud for the back of the CAS. So, I decided to use the support bracket. Seeing also how a certain member here had posted about having the manifolds break without brackets in place, I doubled up on my resolve to re-use this CAS to TB support bracket. It also makes a nice rest for the tube coming from the port on the intake manifold down to the 2G air intake snorkel, that is what the hole in the middle is for.
Out of the 1G intake manifold, 4g61t manifold and the Cyclone manifolds, I used the longest studs I had available because if the JDM 4g63t TB is indeed shorter than the USDM '90 4g63t TB, this would account for the issue I had mounting my CAS/TB support bracket. My bracket ended up looking like this, with the longest (Cyclone ??? or 1G) studs and bolts I could muster up. I now think this is likely either a 4g61t or 4g63t piece but I have no way of confirming unless they piece codes contain a portion of the their ASA/CAPS part numbers. Either way, I modded my bracket to fit, and it was just a fluke that I cut exactly enough to make it work on the first shot. The 10" grinder wheel setup was at work, car was not. So, mounting angles on the flats for the nuts and where they mount seems to have been maintained so as to not be an issue. I did just find a JDM TB in the basement, parts I hoarded when I was finding Cyclone bits to use just in case of issues with the USDM parts I had lying around, or if I had installed it with the 4g61t still in place.
Anyways, this is how it all turned out, and how it will look when it is fired up again just before the snow flies .... again. We've already had a light dusting two days ago. /ubbthreads/images/graemlins/banghead.gif