This is my Extratoy as it arrived. The tub and body are as they should be, but the electronics have been highly modified. The batteries are true sized C cell NiCads bought from a retail store back in the day, and taped together. The electronics have been modified to now use a large heat sink mounted to the rear body mount. So yea, this would be a "toy" RC, but at some point, someone truly modified this. Luckily for me, whomever did these mods, did them nicely and only used stock screw holes (as far as I can see). The car was quickly broken down and all electo-mechanical gizmos tossed in the bin. So, not too long after this made it's way into my world, I ended up with a Tamiya HB, an actual original Tamiya HB.

So, let's compare parts side by side. From here on out, Tamiya parts will be on right, and Extratoy on the left.
Random start, tires. Very similar except the Extratoy stamps a tag of ES-802 between the OFF ROADER stamps. Everything else seems identical.
Now just a series of the "grey" parts used throughout. It is hard to tell in the pics, but the Extratoy parts are a little lighter grey than the Tamiya parts. The wheels are identical mechanically, but the Tamiya ones are a silver'ish, and the Extratoy ones are the same grey as all the other parts. Rear bumpers. Transmission. This one is a little interesting. Note the Extratoy driveshafts are plated (chromed?) and have the extra safety lengths on the ends, and the Tamiyas do not. The Extratoy also came with a trans gear cover, which the Tamiya did not. The Tam I got did not have a motor, and I thought that would be easy to get, but 360/380 motors with nylon endbells aren't out there like I thought they would be. The Extratoy came with a white nylon endbell motor, and the Tamiya should have a black nylon endbell. The body. 80% identical exceopt a) not same color, b) roof top mounting holes slightly different, and c) two piece rear louvers on the Extratoy. Material "feels" identical.
Out of attachment space.