Here's a simple photo comparison of the Patriot Avenger Chassis (MR3002) and the about to be released Avenger X (MR3102) these are 4" Flexi-class chassis.
The Avenger is the chassis on the left, while the Avenger X is the one pictured on the right. The center section is available separately as part number MR3112 and the one-piece pan assembly is part number MR3122. These chassis are intended for flat track racing. They are similar in weight: Avenger 44.4 Grams Avenger X 43.5 Grams. Eagle Distributing has these items currently in stock.