Hobbyboy This rc car is very well built and fast. So I wanted it to go faster and decided to upgrade everything. I bought all the upgrade parts this beast would need, except the motor/gearbox mount. I bought an NHX motor/esc combo at a great price. I started the upgrade and realized the motor mount would not allow the spur gear to easily slide back through the opening. You will have to destroy it! It's a hard plastic or something, but it doesn't flex enough to allow the motor to be removed. It doesn't allow for a pinion puller to be used either. I had to use a flat head screw driver and mangle the mount, trying to get it to stretch. So if you want to purchase this, go ahead. Just remember when the motor dies it can't be easily replaced. Also if you do the upgrades get the longer CVD shafts. They are upgraded to fit the newer differential in the gearboxes. The stock ones are to small. The upgraded parts have bolts and the are different size hex heads. So you will need small and smaller Allenwrenches to use the new hardware or just use the stock ones. Hope this helps some one looking for a sweet little headache.