Cost is relative. The TNT gear is made from T6 aluminum, and is far stouter than most other offerings. Plus, it probably looks better.

I have a set that is on its second SE. The first lawn-darted when I neglected to hook the wings up. The model was low when the wings departed, and the fuselage did a reasonable imitation of a cruise missile that has arrived at its target. I didn't even have time to chop the throttle. It was big-time ugly.

The TNT gear bent slightly. Of course, the pants were trashed, but the gear itself bent back to shape easily and quickly. I built another one, and haven't touched that gear since.

And I didn't reinforce anything. The TNT gear is a direct replacement, although you have to drill the appropriate holes.

The TNT gear is tough, made to be a direct replacement, and works perfectly. IOW, worth the money it costs.