yes, the T3 and T4 are definatly comp cars.
you can't really go wrong with a traxxas car.. they build a good solid truck and for backyard / park bashing (must have missed the 8 year old bit) they would be better than a T4.
The traxxas cars can be "hotted up" to get better performance too.
the e-max is a 4wd
and the stampede is 2wd
2wd will be simpler to maintain.
they have two kits in the RTR stampede
MODEL 3610: Fully assembled, Ready-To-Race®, with TQ™ radio and ProGraphix painted body
MODEL 3606: Fully assembled, Ready-To-Race®, with TQ™ radio, XL-1 ESC and ProGraphix painted body
i personaly would go for the 3606 to get the esc (much less issues than with a mechanical sc)
i just noticed that the e-maxx is a twin engine.
i would go for the stampede just for the simple layout and weight saving
