We have three T's. I have a '27 with a Speedway body, and a '23 with the same brand. My Son has a TP body on his T. We build our own frames because we just build them a little better in our opinion than the off the rack ones, and use heavier tubing.
So, here is my opinion of both companies. TP has built a very successful business with a niche product. They cater to customers who either have the ability to build their own car and only need a few parts , or......they can sell you a car that is just a bolt together if you don't have the means to do welding and fabrication. I am not crazy about their body. I think it is way too thin and wavy. The body shop that painted my Sons had a terrible time getting it straight enough for paint. They told me they were able to paint mine black easier than painting his blue. I also do not like the open flap they leave in the back of the body "to relieve stress." It sort of makes the body like a thin skin on the car in my opinion.
Their upholstery kit is also a nightmare to install. We spent 4 days and had to toss out some of the stuff that came with it to make it work. They have now changed the way they do it, but we bought ours just a year ago and it was terrible. I hope the new one they sell is better. Our vinyl is also starting to pull in some areas and the car only has 4 months and 200 miles tops on it.
Now for Speedway. I have bought from Speedway for over 20 years, and you have to pick and choose what you get from them........some stuff is very good and some is offshore crap. Their chrome is ok, but not nearly the quality you get with SoCal or Pete and Jakes. I have never bought their frames for the reason I mentioned above, but have two of their bodies. Surprisingly, their layup is much heavier and straighter than the TP body we have. Mine only took a very small amount of prep and the body shop sprayed it gloss black. I was really surprised by the fact that it seems thicker and straighter than the TP body. It also has a totally sealed backside, unlike the flap TP uses, and they don't seem to think it will crack. My '27 body is 20 years old and has no stress cracks yet.
I keep hearing good things about Spirit. On most T bucket forums the consensus seems to be that they are very good. I did see one guy who had a problem with the way the steering column mounts to the bottom of the dash, it was breaking away. I don't know if that was an older design that is now changed or not.
But I think with whatever kit you get there is still a good amount of work to make it "right." For the average person maybe the fit and finish is ok out of the box on all of them, but if you are fussy you will want to take steps to make them a little better.
Don