Hi Charlie, I am changing to a TR4A front suspension. I am changing the upper and lower control arms, using Super Pro suspension bushings, upper ball joint, the vertical link, trunnion, brake mounting bracket, and the lower spring pan. The TR3A steering arm will be reused. This swap also lowers the front so a spring spacer will need to be added to the top of the spring . the spacer will be determined once the car is assembled (a long way off). The TR4A components are much stronger. With this swap you have the advantage of the 3 degree trunnion. The trunnion is also mounted to the lower control arms with a bolt that makes future maintenance easier. The brake mount will accept the modern 4 piston Toyota brake calipers as well as larger brake pads. My project is a complete frame off restoration and so while repairing the frame I decided to upgrade the front suspension. I am sure I have left out some details about this upgrade but it is a work in progress. Any questions are welcome. Frank