In order to make sure you do not damage or melt your brake or clutch assembly, follow these instructions carefully. They are already noted in your kit manual, but it is worth checking before your run your car.

New plastic shock bodies and shock caps!

All future runs of our plastic Sport shocks, including all plastic shocks included with our kits, will feature a new thread and cap design for easier installation! The new coarser threads (less threads with a lower pitch) are easier to thread on and prevent cross-threading, which can damage the plastic threads. See the picture below for a comparison!

On the left, the older design

On the right, the newer shock body and cap (NOTE THE GROOVE IN THE NEW SHOCK CAP!)

The new shock cap is part number 72100; the part numbers for the plastic shock bodies will stay the same for all the kits that use them (RS4 Sport, RS4 MT, RS4 Rally, RS4 Mini, etc.). Be sure to note the identifying groove in the new shock cap! This tells you that the shock cap is the new style, coarser thread design. 

#1703 Purple Anodized Heat Sink Head...

If you want to add this part to your car, follow these instructions: Use only ONE head shim, and be sure the notch of the sleeve lines up with the seam of the engine case. This will make sure your engine runs after you install it!

Instruction Manual Typos...

The notation in the back of the Super Nitro RS4 manual about the tuned pipe and header not fitting the 280mm WB car is incorrect. The header will clear the right rear tire just fine on the shorter wheelbase car! If you decide to use wide Super-size tires (available from other companies) on the rear, you will have clearance problems and may need to bend the header, or use a different header.

An update from the HPI Customer Service: There is an incorrect part number listed on the Option Parts list on the back of the Super Nitro RS4 manual. Part number A261 Stainless Steel Hinge Pin Set will not fit the Super Nitro RS4 kits, the set includes two hinge pins that are 3mm too short and is two hinge pins short of fitting the Super Nitro RS4. If you have #A261 and want to fit the stainless steel hingepins on your Super Nitro RS4, you will need these parts in addition to #A261: two sets of #6284 and one set of #6285. This will completely outfit the Super Nitro RS4 with stainless steel hinge pins. The part number for the 'official' stainless steel hinge pin set for the Super Nitro RS4 is #72016.

If you have not bought the #A261 for the Super Nitro RS4, you can save a few dollars by getting two sets of #6282 (3 x 42mm), three sets of #6284 (3 x 30mm) and two sets of #6285 (3 x 28mm) stainless steel hinge pins.