A new short block 2.5 engine $65 and the exchange program is a rip of joke. I have found adding metal skid plates or any other metal parts really adds weight and isn't worth it. I only add the metal spur gear and they just don't hold up that well launching.
I have had no issues with my t maxx's. There just fine for jumping when you set up the suspension right and either engine is good enough power. All I did was drop down 2 teeth and the I have more power. The bulk heads were fixed with the cross brace and improved the hinge pins.