Hi. You are extremely fortunate to have access to an 04 cobra. As you have said, you can use the brakes and hubs. I believe the differential housing is the same except it is aluminum, therefore better. That being said, I believe although I may be wrong, that the cobra diff is a 32 spline and the thunderbird is a 28 spline. However, If you are really clever you can use the cobra rear axles but I do believe they need to be shortened. To be honest I haven't really looked into this option too much. There are no stock replacement differential carrier bushings, so you are stuck with urethane which is not that much stiffer than rubber. I actually had one of those fail at a race and decided to make delrin ones, although I may be pushing the limits of those a bit. the upper control arm bushings are available as well as the lower control arm bushings in a stock style. I can't seem to find the spindle bushings, but as I have said, it isn't going to hurt you too much to go with a urethane bushing as it has almost as much give as rubber in my opinion. you can always check your local autozone and see what they can come up with. I hope this is some help.