>>4613017Depends on what you're doing with the car. The #1 reason to do the 5-lug swap is the infinitely better wheel selection. 5-lug is slightly stronger, if you're doing something where you're snapping the lugs (aka drag racing with sticky tires), and you have the option of going to Cobra brakes, or using any of the other SN95 brake upgrades. Stock SN95 GT/V6 front brakes are no better than foxbody front brakes (if anything they're slightly worse, because they're the same piston/pad/rotor size, but heavier).
I'm not sure what the T-bird spindles are like, either. I'm 90% sure the T-bird A-arms are about an inch longer than Mustang A-arms, which means you can swap to SN95 spindles with no real effect on your camber. With my Mustang, I gained just over a degree of positive camber from the later spindles, which turned the car back into an understeering pig (I've since fixed that).