A_TrackedVehicle is an old implementation which is inferior in most ways to T-26 example. I’ve brought it into MMT from an older project. The only benefit it have is that everything packed into a single BP but it lucks modularity of the new version together with some bugfixes and features like more adequate suspension.
I haven’t used PhysX implementation but recommend looking into it if your goal is performance. It has some quirks but as source code is available you can mod it to your needs. Performance wise it’s really great, I’ve heard people having like 20 tanks roaming around without significant performance impact.