The other bits and pieces that come with the package fit pretty well. Taigen have even tried to improve the return roller fittings. If you've used the ones from the Asiatam/Taigen days, you'll know just how niggly it was to bond to two parts of the rollers together, without glueing the shaft solid at the same time.

... then the next problem emerged of the roller shaft having no real means of being locked in place. Tightening the locking not on the inside of the hull wall, also tightened the pull on the roller..creating annoying friction. Tamiya rollers, by comparison, are a joy to fit, as the shaft has a 'D' profile milled in at the locking end, corresponding with a 'D' recess in the roller housing. Early iterations of the Taigen.Asiatam setup had none of that refinement. Often when whole thing would spin round...even after the judicious use of thread locker.
Now the revised shaft has fluting on the inboard side, which wedges into the plastic of the hull, where the plastic acts as a sort of lock washer.

- Taigen StuG 11 return roller A
But first, it's necessary to relieve the inner (female) part of the outer wheel, to accept the stub of the inner one. I use a slow speed 6mm hand drill for this, and also had to file off a visible burr on the inner stub.
It was a fairly tight fit, but then I greased the shaft with Tamiya ceramic grease, and having dabbed some strong thread locker on the mating surfaces (ooohh.. tank porn, eh?

), pressed them together with some force.... and pliers. the Tamiya grease ensures that everything spins as it should.

- Taigen StuG return rollers pic B
Then fitted the six rollers to the hull.

- Taigen StuG-Six rollers in place
That's pretty much all that's necessary to do at the outset. The kit I got also came with the rear panel (the one that has an inset for the On/Off switch), a complex fast release mechanism, all the required wheels, wheel covers, idlers, and sprockets, together with all the screws necessary to complete the hull furnishings.
For another, £25-30 (or, until Brexit kicks in), you can get an upper Panzer 111 hull, or Stug hull to take the project to near completion.
"Get your facts first, and then you can distort them as much as you please"- Mark Twain.