There will be 2 replacement Chassis' available.
Stage 1: approx. 1 mm shorter ... replacement for all of the world except North America.
Stage 2: Approx. 1 mm shorter, countersunk screw holes underneath and battery slots...available ONLY to the NOrth American market as replacements for their O4R's.
On a side not...if you do not intend on racing TCS...you should get the 414M instead of getting the 04R and adding saddle pack carbon chassis, etc...
The 414M comes with front and mid one way, carbon chassis and aluminum bulkheads (plus many other features)...for much elss than making the 04R the same spec....