Opinions on the t3 big brakes over gslse brakes when converting to 4x114 also their steering rack. Its new so probably not many people have it

 

On the brake part, one advantage of any aftermarket solution would be the availability of parts over the NLA factory parts. The big one here are the calipers. The rears haven't been available for a white and I'm guessing the fronts are probably in the same boat. It's not that hard now-a-days to make a bracket that will adapt a common caliper. The T3 stuff is way too expensive in my opinion.

For the rack, @MTheoryInc has the best setup.

 

Agree. The GSL-SE parts are too hard to find now and the T3 steering kit looks.... not ideal. Look into Mtheory

 

I recommend MTheory's rack kit, been driving with it for 2 years now.

Not difficult to make a bracket, it's the hub integrated with the disk that makes it difficult.
This guy has been racing with their brake kit in E Production:

 

The SE brake parts are no longer an option. Everything related to them is NLA from OEM, and it's been years since the OEM parts were even available including such mundane parts as pad slides, backer plates for pads, and the slider bolts, not to mention the most important part - the caliper itself.

I'd go with something else if you plan to drive the car more than just a nostalgic collector ride. For a track car, definitely something more modern.