The difference is huge. The red RTR chassis is a solid piece of alum. The flex chassis is milled in areas to allow flex and increase traction. When I ran a 1.0 T I ran the stock roller chassis until 2 races before I sold the truck. I installed the flex tuned 1.0 chassis and it made huge improvements in handeling, corner speed and in the bumps. Well worth the money. If you want the newest up to date tech and R/D then go for the BCE 8T 2.0 chassis. I run this chassis now and it flat rocks. Great chassis and even better in the bumps and corners. Check it out. CLICK HERE