Originally Posted by mxgregg
I'm sure I won't I was just wondering what the differences are
Perhaps you could have looked on TamiyaUSA.com?
42200 TRF417 w/ Gear Diff Unit (this is the $400 on-sale version)
At the 2011 Thailand International R/C Touring Car Championship (TITC) held in February, TRF (Tamiya Racing Factory) drivers raced their TRF417's with a new Gear Differential Unit installed in the car. Tamiya now offers the TRF417 with this unit as a standard option part included with this new spec version of the TRF 417.
This is the latest spec TRF 417 machine. The main enhancements incorporate subtle revisions. A newly-designed lower deck offers improved chassis flexibility for better low-speed traction. The previous one-piece motor mount has been replaced with a three-piece type to allow further adjustment of chassis' flexibility by linking them together. The thickness of the front and rear damper stays have been increased to 3.5mm and other new developments include a new upper deck, metal battery holders which serve as counterweights, and low-height kingpins. Front direct coupling and rear gear diff unit (Item 42197 TRF417 Gear Differential Unit II) are included in this latest spec version
The MACH Circuit in Heemstede, the Netherlands played host to the seventh biennial IFMAR ISTC World Championships from July 26th-28th. Of course, Tamiya Racing Factory (TRF) was in the thick of the action and when all was said and done, TRF driver Jilles Groskamp and his TRF417X was crowned the champion. Not only was this Tamiya's third consecutive victory at this prestigious event, it also brought its total IFMAR touring car title count to five (2002, 2004, 2008, 2010, 2012). The TRF417WX edition kit brings enhancements used during the world championship to customers around the world who choose to race the best touring car platform on the planet.
Newly designed carbon fiber upper (2.0mm thick) and lower (2.25mm thick) decks feature refined shapes to provide optimum roll flexibility.
Newly-designed one-piece aluminum servo mount is secured to the chassis by one side (inner side) only so as to not jeopardize chassis flexibility.
Newly-designed aeration dampers help maximize traction.
Front and rear carbon fiber damper stays (3.5mm thick) have redefined damper attachment positions.
Front direct coupling is equipped with steel cup joints and coupled with Double-Cardan drive shafts to provide efficient, smooth power transfer.
Rear gear differential features steel diff joints and swing shaft protectors.