If you poke speed holes into the slide it'll go faster.....
Just kidding...if you want to put a 5.1 slide on it you'll need:
1. Slide w/ bushing
2. Blowback chamber w/ piston head and retaining screw *
3. Nozzle *
4. Nozzle return spring *
5. Float valve *
6. Float valve spring *
7. Hopup unit/hopup rubber *
8. Inner barrel
9. Outer barrel
10. Full length guide rod
11. Recoil spring
12. Front sight **
13. Rear sight
The items with a * can be gutted from the 4.3 slide. The item with the ** can be...but it's not the right sight.
The other items you'll have to buy new. Good luck finding a rear sight...
Note: Even though the parts work in the stock TM slide...doesn't mean they'll just drop right into an aftermarket slide and just work. If you're lucky...they will. If you're unlucky they never will...no matter how much fiddling, filing, tweaking you do.
I cannot comment much on the Davidson custom slides. Only that a customer is having a bitch of a time with his and we're dropping all the internals back into a stock TM slide to get the pistol shooting again. That does not mean they're all bad....I've had Shooters Design and other top brand slides not work well as well.
Best of luck with your build.
NOTE: You don't need a fancy gun to shoot CAPS...some of our best shooters shoot stock pistols and two of our best ones shoot stock ones that are pretty much broken (M9 and G26). Some guys who shoot slower....like to have something pretty to compensate....