Main differences between RB5 Sp and Worlds kit
 

As the title suggests, aside from the big bore shocks, slipper plates and anodizing colour.

Cheers
Brian

Plus

Longer front suspension arms, suspension mount narrowed, one piece front axles, Different Front Shock Tower for the big bores.

probably more buts that's all i can think of at the mo.

just found this on the kyosho website that may help further?

List of new parts used to improve the kit. Use these parts to update your RB-5 SP2 to WC:

LA251 Kyosho Lazer ZX-5 SP Blast Wing 6.6" High Down force
LA221HB Kyosho Ultima and Lazer Hard Aluminum Servo Saver Set
LAW30GM Kyosho Aluminum Clamping Wheel Hubs Gunmetal
UM520 Kyosho Carbon Composite Short Rear Shock Tower - RB5 SP
UM525B Kyosho Ultima Big Bore Front Shock Stay
UM566 Kyosho Ultima RB5 SP WC Middle Suspension Arm Set
UM567 Kyosho Ultima RB5 SP2 WC Front Suspension Mount Type C
UM568 Kyosho Ultima RB5 SP2 WC Type-C Hard Aluminum Front Hinge Pin Brace GunMetal
UM569 Kyosho Ultima RB5 SP2 WC Steel Axle Shafts
UM570 Kyosho Ultima RB5 SP2 WC Slipper Disk
UM571 Kyosho Ultima RB5 SP2 WC Red Slipper Sheet
UM572 Kyosho Ultima RB5 SP2 WC Slipper Spring

Brian, Do you mean the SP2 and the Worlds kit?

If so, the WC has the following changes:

• Narrow front pivot block
• Longer Front wishbones
• New one piece wheel hex/shaft - narrow hex
• longer front shock tower (big bore front shocks are slightly longer)
• New stiffer Servo saver plastic

Rear end geometry is the same

Think thats it!

Kev

Brian - what are you trying to achieve?
Bodyshell is different too but I am sure Brian is not going to run a standard RB5